Venial sin does not diminish sanctifying grace in our souls. When we sin venially, we are still God’s friends- pretty mean friends, at times, it is true, but still friends- and so we do not lose or diminish sanctifying grace. Venial sin does not diminish it in even the lightest way; and so even after having committed 1,000 or 1,000,000 venial sins we still have the same amount of sanctifying grace as when we started.
So! It is all right then to commit venial sin then??? Not at all,
- On the grounds of decency. It is a pretty mean
friend who doesn’t care how much he offends another
friend provided he doesn’t lose his friendship,
wouldn’t you think?
- On the grounds of theology. We prove ourselves
unworthy of God’s special graces which we all need
to conquer serious temptations when they come,
and to practice virtue under trying circumstances.
- On the grounds of merit. By sinning, we fail to practice virtue and so fail to grow in grace, lessening our happiness throughout all eternity.
- On the grounds of psychology. By repeated venial sin, especially along one definite line, we grow weaker psychologically, i.e., we yield more readily to the sinful attraction each time it comes. The result is that if a strong temptation to a mortal sin comes along, we are most apt to yield.
For example: a tank of water is supported by wooden supports. The tank is full of water. Termites begin to eat away the supports. No water is lost. The tank may remain a long time on the weak supports. But if a big wind come! Then this “big wind,” which is a serious temptation to which the could actually yield, knocks over the tank, smashes it, and all the water (grace) is lost. None of it was lost through the termites, i.e., venial sin, but all of it was lost by yielding to the big wind.
Let’s Look at Sanctifying Grace – Francis P. Le Buffe, S.J. Queen’s Work Publication 1944