21 These things I am compelled to admonish by reason of certain little discourses of some men, that are to be shunned and avoided, which have begun to steal through the ears unto the minds of many, being (as must be said with tears) hostile to the grace of Christ, which go to persuade that we count not as necessary for us prayer unto the Lord, that we enter not into temptation. For they so essay to defend the free will of man, as that by it alone, even without help of the grace of God, we are able to fulfill what is commanded us of God.
And thus it follows, that the Lord in vain said, “Watch and pray, lest ye enter into temptation;” and in vain daily in the Lord's Prayer itself we say, “Lead us not into temptation.” For if it is of our own power alone that we be not overcome by temptation, why do we pray that we enter not, nor be led into it? Rather let us do what is of our own free will, and most absolute power; and let us mock the Apostle, saying, “God is faithful, Who will not suffer you to be tempted above what you are able;” and let us oppose him, and say, Why seek I of the Lord, what He has set in my own power?
But far be it, that he be so minded, who is sound minded. Wherefore let us seek that He may give, what He bids us that we have. For to this end He bids us have this, which as yet we have not, to admonish as what to seek; and that when we shall have found the power to do what He has bidden, we may understand, of this also, whence we have received it; lest, being puffed and lifted up by the spirit of this world, we know not what things have been given unto us of God. Wherefore the free choice of the human will we by no means destroy, when the Grace of God, by which the free choice itself is helped, we deny not with ungrateful pride, but rather set forth with grateful piety.
For it is ours to will: but the will itself is both admonished that it may arise, and healed, that it may have power; and enlarged, that it may receive; and filled, that it may have. For were not we to will, certainly neither should we receive the things that are given, nor should we have. For who would have continence, (among the rest of the gifts of God to speak of this rather, of which I am speaking to you,) who, I say, would have continence, unless willing? Forasmuch as also no one would receive unless willing.
But if you ask, Whose gift it is, that it can be by our will received and had? Listen to Scripture; yea, rather, because you know, recollect what you have read, “Whereas I knew,” says he, “that no one can be continent, unless God give it, and this itself was of wisdom, to know whose gift it was.” Great are these two gifts, wisdom and continence; wisdom, forsooth, whereby we are formed in the knowledge of God; but continence, whereby we are not conformed unto this world. But God bids us that we be both wise and continent, without which goods we cannot be just and perfect.
But let us pray that He give what He bids, by helping and inspiring, Who has admonished us what to will by commanding and calling. Whatsoever of this He has given, let us pray that He preserve; but what He has not given as yet, let us pray that He supply; yet let us pray and give thanks for what we have received; and for what we have not yet received, from the very fact that we are not ungrateful for what we have received, let us trust that we shall receive it. For He, Who has given power unto the faithful who are married to contain from adulteries and fornications, Himself has given unto holy virgins and widows to contain from all sexual intercourse; in the case of which virtue now the term inviolate chastity or continence is properly used.
Or is it haply that from Him indeed we have received continence, but from ourselves have wisdom? What then is it that the Apostle James says, “But if any of you lack wisdom, let him ask of God, Who gives unto all liberally, and upbraids not, and it shall be given unto him.” But on this question, already in other little works of ours, so far as the Lord has helped us, we have said many things; and at other times, so far as through Him we shall be able, when opportunity is given, we will speak.
Source: On the Good of Widowhood (New Advent)