1265–1273 · Thomas Aquinas, Summa Theologica I-II, q. 65, a. 5, co.
I answer that, Charity signifies not only the love of God, but also a certain friendship with Him; which implies, besides love, a certain mutual return of love, together with mutual communion, as stated in Ethic. viii, 2. That this belongs to charity is evident from 1 Jn. 4:16: "He that abideth in charity, abideth in God, and God in him," and from 1 Cor. 1:9, where it is written: "God is faithful, by Whom you are called unto the fellowship of His Son." Now this fellowship of man with God, which consists in a certain familiar colloquy with Him, is begun here, in this life, by grace, but will be perfected in the future life, by glory; each of which things we hold by faith and hope. Wherefore just as friendship with a person would be impossible, if one disbelieved in, or despaired of, the possibility of their fellowship or familiar colloquy; so too, friendship with God, which is charity, is impossible without faith, so as to believe in this fellowship and colloquy with God, and to hope to attain to this fellowship. Therefore charity is quite impossible without faith and hope.