Honor and glory belong to God alone, but God will receive neither if they are not sweetened with the honey of love. Love is sufficient for itself; it gives pleasure to itself, and for its own sake. It is its own merit and own reward. Love needs no cause beyond itself, nor does it demand fruits; it is its own purpose. I love because I love; I love that I may love. Love is a great reality, and if it returns to its beginning and goes back to its origin, seeking its source again, it will always draw afresh from it, and thereby flow freely. Love is the only one of the motions of the soul, of its senses and affections, in which the creature can respond to its Creator, even if not as an equal, and repay his favor in some similar way. For example, if God is angry with me, am I to be angry in return? No, indeed, but I shall tremble with fear and ask pardon. So also, if he accuses me, I shall not accuse him in return, but rather justify him. Nor, if he judges me, shall I judge him, but I shall adore him; and in saving me he does not ask to be saved by me; nor does he who sets all men free, need to be set free by me. If he commands, I must obey, and not demand his service or obedience. Now you see how different love is, for when God loves, he desires nothing but to be loved, since he loves us for no other reason than to be loved, for he knows that those who love him are blessed in their very love. Although the creature loves less, being a lesser being, yet if it loves with its whole heart nothing is lacking, for it has given all.
Bernard of Clairvaux, On the Song of Songs IV, Sermon 83 – II. How the affect of love is more powerful than other affects. v. 4, 6 (CF 40, pp. 183-184, 186)