Being faithful is not about being without sin (impossible), it's not about being without error doing everything perfectly, it's not about being the most holier than thou person you can be, it's not about putting up a show for the world/ others/ anyone to see how good and "Christian" you are (neither is it about putting up a show of praising self about how 'low' you are compared to God, as in look at me I am so humble, that's disguised pride too). But being faithful is all about YOU being being faithful to God in YOUR walk WITH Him, it's about knowing/ being aware that you will give an account of yourself to God (Romans 14:12). It's about wanting to please Him and trusting in Him, to listen to the Holy Spirit working in you, to learn from Christ His stewardship and ministry here on earth, to then also be faithful in your walk with God and be faithful with the stewardship that God has given you in your life, it's about how you respond to God, this world and all that happens to you/ your life, it's about your attitudes in your day to day walk with and in Christ.
It's not about doing great works of your own, as you only need to step into the works that God lays in front of you (He prepared them for you). And it's not about being perfect or without error, but it's about being faithful to God, to listen and follow His Holy Spirit. The people losing out on the inheritance of entering the Holy land was not about being sinners or not, or about doing great works or not, it was all about a lack of faith in God, rejecting God and His plans by not trusting in Him. They did not yield to God but instead grumbled against Him, placing bad attributes on God and blaming Him. Their lack of faith resulted in them losing out on their inheritance (not their justification, being saved), having to stay in the wilderness. Even to the point of saying that they were better of as slaves in Egypt and that God only brought them into the wilderness to let them die off, having no faith in God to bring them into the promised land, having no faith in God that He would protect and guide them with/ through whatever temporary obstacle they would encounter.
And it's easy for a believer today to say; that's blasphemous I would never say or do such things. But through our actions and in the things we say, and in our attitudes and and the way we respond to God, we too can be guilty of lack of faith in God. Do we pray FOR someone or against someone? Do we blame God or do we thank and praise Him? Do we accept tribulation/ hardships and all that God places in front of us (including people that oppose Christians) or do we try to fight against it in hopes that it goes away? Do we lay everything at Gods feet and give Him the glory, and trust in Him, in His ways, in His timing? or do we want to do and fix everything ourselves, and (try to) do that on our own accord, on our own timing, the way we want it? Do we accept corrections and training by the Holy Spirit or do we walk away from it? What is our attitude when things are fine? What is our attitude when things go bad? What is our attitude when everything seems to fall apart and seems "impossible"? And being faithful or not is not about being saved or not, as everyone with the Holy Spirit is sealed, saved and justified. A walk of faith, a Christian walk, is about a lifelong sanctification process resulting in possibly obtaining the inheritance or not. It's about every believer who can be a 'son who inherits' (it's not about physical males, and it's not about literally being firstborn in your earthly family, it's a type). It's about heirs who are in bootcamp training here on earth, being trained for future tasks and responsibilities in the future kingdom to come, wanting and trying to be faithful to God. In opposite of faithless believers who lose out on the inheritance because this life, world and self is all that matters, who walk away from God, who have no trust/ faith in God but rely on themselves (or on other things like political leaders to save and help them).
Eventhough faithfulness is not an exact measurement, you could say that for a faithful Christian their mind is set on God >wanting/ trying< to please and serve Him (by faith). Which does NOT mean you are without sin, or without temptations, or without error, or without the strings of the world pulling on you, or without earthly/ fleshly desires, it does not mean your own works are great, and does not mean you have to quit your job and be studying the Bible 24/7 or be in ministry 24/7. One difference is faithless people do not really care about God and what God wants. Often times faithless people do not really like the role of servantship and sonship, which both requires obedience and letting go of self, to be able to receive and accept corrections and training. To some it would then even be a nuisance to be in the process of sanctification by God, because God is then standing in the way of all the things they want, or the things God wants are too much trouble or too difficult in their eyes to then walk away from God and the things He wants. They may have come to Christ at one point in their life but God is just a small part in their lives when it's convenient and/ or when it's easy, and therefore do not yield to His Spirit, to His teachings, His training and His corrections by and through His Spirit.
And again, a walk with God is not about your own great works (for example: look at me and my career!, look at this number that I donated!) and spending time with Him does not mean you have to be reading the Bible all day long or be in ministry 24/7, it's all about following His Holy Spirit, yielding to it and it's teachings, training and corrections, by keeping the faith, not blaming God, not placing bad attributes on Him. If you are faithful you will enter this tug of war "fight" and keep running the race until the end, and when you fall (we all do), you repent and get back up again, staying close to God, and that faithfulness is a day to day thing in all aspects of your life. And this getting back up, running the race again, staying close to God, going back to Him, that is one of the most important parts. God does not want you to walk away, He does not want you to dwell and drown in guilt. He wants you to learn and stick close to Him, so when you do fall, which we all do, you get back up, you confess and repent to God, you stick to God, you keep choosing God, all the way until the end.
Besides being faithful to Gods Spirit (to His teachings/ training/ corrections in/ on you), every person has a stewardship that differs from person to person, so I cannot tell you what God has given you in your life to take good care of. It's not about everyone having to be a pastor, or being in ministry, or being a missionary in a foreign country, or being a street/ online evangelist (these things CAN of course be your calling and be part of your stewardship, and if it is, do yield to it), there are many more things God can give/ has given you to take good care of; people (family, spouse, children, colleagues, classmates, customers, neighbours, etc, can be anyone), pets, (free) time, work/ job, even money (not the love for it, not personal profit of it, but money can/ should be used for good instead of just personal pleasure, Joseph is a good example of a good steward, stewarding Pharaoh's possessions, God can give you wealth to use for good), skills, gifts, spiritual calling(s), wisdom, and so many many more things that you can take good care of, as God has given it to you, as a steward over Gods possession(s) here on earth.
For example: do you take good care of your spouse, of kids, of colleagues, of classmates, of friends, strangers, pets etc. Take good care of everything in your stewardship as Christ did, having Him as your example, being kind, being humble, loving, caring, showing mercy, showing grace, serving, helping out. And it's not about others deserving it or not. And it does not have to be grand things, even things like taking good care of your pets. They all are part of Gods creation and are Gods possession and can be part of your stewardship, as God placed them in your care, in your stewardship. How many parts of Gods creation get treated horribly; animals, pets, children, spouses, family members, colleagues, classmates, literally anyone alive for that matter, and yes including Gods created nature. When for example you love and take good care of your pet(s) and make sure it's needs are fulfilled all the way until the end, to the best of your ability with the resources that are available to you, then you are a good steward regarding this part of your stewardship, and you are taking good care of the possession God entrusted you with. It's not always easy or straightforward but there is caring, trying and coming short. And there is not caring about the things of God because it's all about self and own wants.
And stewardships can therefore also change over time, people come people go, pets come pets go, different callings can come later on in your life or when you are further in your walk with Chirst. For example, when it is time for a pet to go, maybe after a while you feel the Holy Spirit calling you to take in another pet, it wouldn't be a replacement, but it then becomes a change in (and part of) your stewardship, who then needs your care and is dependent on you to take good care of it. Or maybe you feel the Holy Spirit calling you to another path, to another task, or maybe you feel a call for multiple tasks. Therefore it is important to pray about all things and ask God what He wants from and for you, to ask for His will to be done, and to then listen to His Spirit and step into the 'works' that God lays out in front of you. Sometimes it can take a while before it becomes clear and get an answer. Sometimes God simply wants you to be 'sitting in the waiting room' and be ready 'to go in' when called. For example maybe the pet God wants you to take good care of, and has been appointed by Him to you and your stewardship, simply has not been born yet, or is not ready yet, or has not reached the point yet for you to take over/ step into, or maybe you are the one who is not ready yet for a specific task God wants you to do in the future, maybe God is doing some work on you to prepare and make you ready for a future task. Whatever it is, pray about it and lay it at Gods feet and follow His Spirit, His instructions.
We all are going to give an account of ourselves to God, about how we lived our lives, regarding our faithful walk with God and the stewardship we had (for believers; this is not a judgement about justification or being saved or not, this is about rewards (by faithfulness) and inheritance (by submission to, and sanctification by, the Holy Spirit, yielding to His training and corrections, not walking away from it). And the important thing about this is, God is not looking if you did everything completely right and without any error or mistakes, what matters is the condition of your heart and mind; did you care? did you try? did you care about God and the things He wants? did you try to take good care of the things God gave you? did you try to take good care of the things God entrusted you with? did you try to yield to His Holy Spirit when it trained and corrected you?
And we all come short, we all stumble, we all fall, we all make mistakes, we all can do more, we all can do better, and we all commit sin. But we confess to God, ask forgiveness and help, and then get back up and run the race again. People for example who are just and only sunday Christians and are (for the rest of the week/ days) busy with the cares and pleasures of this world, may actually be saved and be sealed by the Holy Spirit (God only knows). If at one point in their life they came to Christ they will (how lukewarm they may be) still be saved as they are justified thanks to Christ and His work on the cross, but they are in danger of losing out on rewards and/ or inheritance since they are not yielding to God and His sanctification work on them. It can be compared with marriages, as the day of the wedding is not the end all be all what marriage is all about, in fact, the wedding is the start of a lifelong marriage, of a faithful walk with your spouse, a walk whereby everyday you choose and stick with your spouse, same as coming to Christ and being justified/ sealed by Gods Holy Spirit is the start of your faithful walk with God, to then choose God day by day entering this sanctification process by: trusting in Him, sticking with Him, submitting to Him, submitting to His corrections, submitting to His training and teachings.
The lukewarm and faithless can be compared to a human marriage as well, as someone who takes and lives just for him/ herself within a marriage, not giving a thought about their spouse and their marriage, and not living out marriage as an unified couple, but just lives for self and for gain, this person may have said 'yes' at the wedding, and is therefore sealed in marriage, but lives as if the marriage does not exist, maybe on just a few occasions with for example some family/ holiday/ feast days, but this persons heart and mind is not in it, this person has no day to day walk as an unified married couple and does not care about it. Some say these people have never been saved to begin with, but the Bible shows people can walk away from the faith and that people can be faithless, and because of Christ and the Holy Spirit they ARE sealed and will be saved, but these people may lose out on the inheritance. Again, that's different from caring, trying and failing and not doing and not being perfect, so don't judge and 'kick down' your spouse for imperfections or for failings, instead encourage and guide/ help him/ her, and also encourage and help each other in your walk with God.
But for the faithless it's not too late to turn around and take your walk more serious. To take your walk of faithfulness to God and being faithful with your God given stewardship here on earth more serious. And as long as you are living it's never too late to turn to God and say; God, guide and help me in my faithful walk and in my stewardship here on earth. As God will provide, He will give/ guide/ help you in all that you need in order to please Him by faith. In your relationship with God, He will lead, He will guide, He will provide. And you submit to Him, stick to Him, and follow Him, in faith(fulness) and by submitting to your God given stewardship and trying to be a good steward over it.