22 But the pleasure of the Creator, of which is written, “And from the river of Your pleasure will You give them to drink,” is of far other kind, for it is not, like us, a creature. Unless then its love be given to us from thence there is no source whence it may be in us. And consequently, a good will, by which we love God, cannot be in man, save in whom God also works to will. This good will therefore, that is, a will faithfully subjected to God, a will set on fire by sanctity of that ardor which is above, a will which loves God and his neighbor for God's sake; whether through love, of which the Apostle Peter makes answer, “Lord, You know that I love You;” whether through fear, of which says the Apostle Paul, “In fear and trembling work out your own salvation;” whether through joy, of which he says, “In hope rejoicing, in tribulation patient;” whether through sorrow, with which he says he had great grief for his brethren; in whatever way it endure what bitterness and hardships soever, it is the love of God which “endures all things,” and which is not shed abroad in our hearts but by the Holy Spirit given unto us. Whereof piety makes no manner of doubt, but, as the charity of them which holily love, so the patience of them which piously endure, is the gift of God. For it cannot be that the divine Scripture deceives or is deceived, which not only in the Old Books has testimonies of this thing, when it is said unto God, “My Patience are You,” and, “From Him is my patience;” and where another prophet says, that we receive the spirit of fortitude; but also in the Apostolic writings we read, “Because unto you is given on behalf of Christ, not only to believe in Him, but to suffer for Him.” Therefore let not that make the mind to be as of its own merit uplifted, wherewith he is told that he is of Another's mercy gifted.
Source: On Patience (New Advent)