The heart requires the intelligence, and therein, says Augustine, lies the difference between the singing of men and of birds. For a linnet, a nightingale, a parrot may sing well, but it will be without understanding. Now the particular gift of man is to sing knowing what he is saying. After the intelligence must follow the heart and the affection, which cannot be unless we have the hymn imprinted on our memory, in order never to cease singing. (Jeremy Begbie quoting John Calvin, in Resounding Truth, p. 110)