Many people, in fact most people, including Christians find it difficult to live the so called Christian lifestyle. And indeed there is nothing more difficult than to live striving towards holiness. That is where grace comes in. We are to be sanctified, not to sanctify ourselves or our efforts. Does this mean then that people cannot or should not strive to live accordingly? No. Of course not. Simply because grace works in mysterious ways and the most recalcitrant heart can be brought to submission by the in breaking of grace into their lives. What this means is that people cannot live devoted to their own egos (or the service of other peoples egos) and also be capable of living a holy, grace filled life. There must be a moment when our commitment to self-interest gives way to our commitment to living a grace filled, holy life. There is nothing in the world harder to do because we are sinful beings by nature. This is why Jesus Christ had to become the atonement for our individual sins. He became the self-interest that we each embrace in our own ways while on the cross, and it was there on Calvary that our self-interest was conquered, through him. We have but to accept the grace that was meant to replace the hole that will be left when we abandon our self-interest.
With this in mind, Christians need to remember than when dealing with the recalcitrant heart in others, not to mistake it for being laziness or a desire not to practice self-control. Indeed self-interest requires tremendous self-control. I have always said of atheists (for example) that it takes tremendous willpower to choose every day to live utterly devoted to self-interest. While it is true that we are sinners, and that our nature is to show self-interest, it is more true that we were meant for something more. That something is Jesus Christ and in this we find our true self-interest, rightly aligned and in proper working order.
But what of the non-believer who does charity? Here is the thing, people can live for others and still be devoted to misaligned and malformed self-interest, as is the case for those who are not homosexual but who champion homosexual marriage on the grounds that people should be free to live as they please. This is nothing less than radical autonomy and ego run amuck. It is subverting truth, for the idea of self-interest, even as the self-interest serves someone else. The same can be said for people who while in a good marriage, seek to make divorce easier for others.
It is therefore a mistake to believe that those who do not believe, or who are hostile are lazy or lack self-control in a general sense. What they do lack is self-restraint, and I believe there is a difference between self-control and self-restraint.