14 The dove teaches us. From the head of the Lord she answers, and says, You have baptism, but the charity with which I groan you have not. How is this, says he, I have baptism, and have not charity? Have I the sacraments, and not charity? Do not shout: show me how can he who divides unity have charity? I, says he, have baptism. You have; but that baptism, without charity, profits you nothing; because without charity you are nothing. The baptism itself, even in him who is nothing, is not nothing. Baptism, indeed, is something, aye, something great, for His sake, of whom it is said, “This is He that baptizes.” But lest you should fancy that that which is great can profit you anything, if you be not in unity, it was after He was baptized that the dove descended, as if intimating, If you have baptism, be in the dove, lest what you have profit you not. Come, then, to the dove, we say; not that you may begin to have what you had not before, but that what you did have may begin to profit you. For you had baptism to destruction without; if you shall have it within, it begins to profit you to salvation.
Source: Tractates on the Gospel of John (New Advent)