11 Let then thus much suffice concerning those outcasts; and now let us return to the divine Scriptures, and let us drink waters out of our own cisterns [that is, the holy Fathers], and out of our own springing wells. Drink we of living water, springing up into everlasting life; but this spoke the Saviour of the Spirit, which they that believe in Him should receive. For observe what He says, He that believes in Me (not simply this, but), as the Scripture has said (thus He has sent you back to the Old Testament), out of his belly shall flow rivers of living water, not rivers perceived by sense, and merely watering the earth with its thorns and trees, but bringing souls to the light. And in another place He says, But the water that I shall give him, shall be in him a well of living water springing up into everlasting life,— a new kind of water living and springing up, springing up unto them who are worthy.
Source: Catechetical Lectures (New Advent)