He comes in three ways: through a knowledge of the truth; through the affection of love; and through imitative action. And in each day it is necessary that one hear and learn. The one who comes through a knowledge of the truth must hear, when God speaks within: "I will hear what the Lord God will speak within me" (Psalm 84:9); and he must learn, through affection, as was said. The one who comes through love and desire -- "If any one thirsts, let him come to me and drink" (below 7:37) -- must hear the word of the Father and grasp it, in order to learn and be moved in his affections. For that person learns the word who grasps it according to the meaning of the speaker But the Word of the Father breathes forth love....One comes to Christ through imitative action, according to: "Come to me, all you who labor and are burdened, and I will refresh you" (Mt 11:28). And whoever learns even in this way comes to Christ: for as the conclusion is to things knowable, so is action to things performable.
[St. Thomas Aquinas, Commentary on the Gospel of John, Chapters 6-12, Larcher & Weisheipl, trs. CUA Press (Washington, D.C.: 2010) p. 37.]