One of the problems with the idea that salvation is free and guaranteed for life, is that it sounds like a licence to let its recipients do what they like. Here are some reasons why it couldn't work any other way.
Can God afford to take the risk of guaranteeing a person salvation? If God guarantees salvation is he not giving a licence to do evil? Would it not be better for God to leave people in doubt so that they would be forced to behave themselves for fear of missing out on the day of Judgment?
These questions seem more than reasonable to the non-believer but they are the kinds of questions only a non-believer would ask.. Here are some reasons why they are wrong.
Men are control freaks. The idea that one has to earn salvation leaves men with lots of creative ways to exploit one another. This has been the basis for all kinds of superstitions and religious manipulation throughout the centuries, where self-appointed priests and gurus become the keepers of the keys to heaven. They pretend to be able to offer salvation to anyone willing to play their silly games, giving them wealth, power and status in the process. When salvation is given freely you have nothing to offer except the truth, and nothing to gain except the joy of seeing others truly saved.
Men are proud: Believing I might be able to earn my salvation by my own efforts provides an excellent opportunity for all kinds of spiritual one-up-man-ship. Competition of this nature has done little to bring harmony on earth, its unlikely to achieve it in Heaven.
Men don’t want to be beholding to God: We all think that making another person obligated to us by doing him a favour is more likely to succeed than relying on his generosity. That might work with man but anyone who thinks they improve their chances with God that way doesn’t realise how incredibly generous God is. How much do you think the creator of the universe needs from you? How much do you think heaven is worth? What would you prefer, that which you could afford, or that which God can afford to give you?
Men are prostitutes. The trade in love has been going on for as long as man has been on the planet, but everyone knows that the love you buy is cheap and tawdry. It is insulting to any human with dignity to be offered money for love, how much more so is it to suggest you can buy it from God!
Men don’t understand themselves. We think the best way to get us to behave is to create more and more laws, yet we hate people making us do things we don’t want to do. God wants us to do what is right out of love—that would be impossible if he held judgment and death over our heads. He is our Father, not a heavy handed policeman.
Men are deluded. Most men gain comfort from the delusion that God will judge them according to the standards and values of the society they live in. However his standards are nothing less than moral perfection. This applies to what we do, say and think. The Bible says no one will be justified by obeying the law, all the law does is show just how hopeless our case is.
True believers can be trusted with a guarantee of salvation, not because they are any better than non-believers, but because they realise just how much God loves them and how much they have been forgiven.
Ironically, they are free to do what they want, but what they want to do is to be better people for the one who gave them life and forgave their sins. They know they can never pay him back but they have found real delight in seeking to do things his way because they love him and delight in any opportunity to put a smile on his face.