The greater the grace, the more abiding it is

The very fact of falling away from the love of God by sin, does not work unto the good of all those who love God, which is evident in the case of those who fall and never rise again, or who rise and fall yet again; but only to the good of “such as according to His purpose are called to be saints,” viz. the predestined, who, however often they may fall, yet rise again finally. Consequently good comes of their falling, not that they always rise again to greater grace, but that they rise to more abiding grace, not indeed on the part of grace itself, because the greater the grace, the more abiding it is, but on the part of man, who, the more careful and humble he is, abides the more steadfastly in grace. Hence the same gloss adds that “their fall conduces to their good, because they rise more humble and more enlightened.”

Thomas Aquinas, Summa Theologica (Part III, Question 89, Article 2, Reply to Objection 1)