Are we obliged not only to do good, but to do what is best?
As I remarked in a previous post on Fr. Peter's article on discerning one's personal vocation, he gives as the first (and least) reason for discernment, that we are obliged to discern what is best.
If God has a preference, am I not obliged to try to discover what it is? After all, his preference is for whatever is best for me… Even though I am only considering morally good options, I should try to find out which one of them is best. Why is this reason the least helpful as a motivation? Since we are considering only morally good options, any failure to discover and choose the best one would not be the matter of a mortal sin [but only a venial sin].
Is it really true, though, that we are obliged to do what is most perfect, so that it is a venial sin to fail to do so? Isn't the difference between a commandment and a counsel, precisely that the commandment obliges us to do some good (or to refrain from some evil), while a counsel invites us to do something good. "A commandment makes the transgressors of it culpable; counsel only makes such as do not follow it less worthy of praise; those who violate commandments deserve damnation, those who neglect counsels deserve only to be less glorified." (St. Francis de Sales, Treatise on the Love of God VIII, ch. 6) Of course in a particular situation it may not be appropriate to follow a particular counsel. "God does not want each person to observe all the counsels, but only those that are appropriate to the diversity of persons, times, occasions, and abilities, as charity requires; for it is charity, as queen of all virtues, all commandments, all counsels, and in short, of all laws and all Christian actions, that gives to all of them their rank, order, time, and value." But supposing that in a particular situation a counsel is more in keeping with love, it seems that then it is still necessary to keep it. If love is commanded without limit, it seems that once we recognize that something is truly the better thing to do, more in keeping with love in a concrete situation, we are obliged to do it.
St. Thomas takes up this difficulty in his commentary on Matthew 19:10, "He who can take it, let him take it" (referring to the counsel of continence). He says, "Isn't every one bound to keep virginity? It seems so, since man is bound to what is better. In response it should be said that it is not a precept, but a counsel, as the Apostle says in 1 Cor. 7:25, 'Concerning virgins I do not have a precept from the Lord, but I give counsel.' But what is this? Isn't man bound to what is better? I say that one must distinguish that which is better in regard to act, and in regard to affection. Man is not bound to what is better in regard to act, but in regard to affection, since every rule and ever act is determined to something definite and certain; but if a man were bound to what is better, he would be bound to something uncertain. Hence with regard to external acts, since he is not bound to something uncertain, he is not bound to what is better. But as regards affection, he is bound to what is better. Hence one cannot not wish to be always better, without falling into contempt."
But if someone knowingly fails to do what is better, doesn't that show a lack of will to become better, to grow in love? St. Thomas says in Quodlibetal I, q. 7, a. 2, "those who are perfect in the sense of having perfect charity are bound by an interior law to do that which is better, a law that binds by way of inclination." To this we must admit that it does show a weakness of the will to grow in love, but weakness of that will does not mean a simple absence of it. As St. Francis de Sales says, "we may indeed without sin not follow the counsels, on account of the affection we may have to other things… it is lawful for a man not to sell what he possesses to give to the poor, because he has not hte courage to make so complete a renunciation."
Mortal sin, venial sin, and imperfection
There is a difference, then, between mortal sin, venial sin, and imperfection. A mortal sin means turning away from God, loving something else in a manner incompatible with the love of God above all things, so that one's life becomes totally directed to something other than God (e.g., pleasure, power, fame) or at least dispersed and no longer centered on God; a venial sin means loving something in a manner that doesn't quite fit with the love of God, yet is compatible with it–one's final end remains God, but one is too much attached to something which is a means to God. An imperfection means only choosing something that is not as well directed towards God as something else would have been, choosing something that is a longer and slower way, as it were, towards God–but still a good choice, act, and way towards God.