4. This sentence derives from two lines of verse in the poem ‘
Enoch Arden’ by
Alfred Tennyson: ‘He will repay you: money can be repaid; / Not kindness such as yours.’ See
The poems of Tennyson. Ed. Christopher Ricks. 3 vols. Harlow 1987, vol. 2, p. 634. Quoted again in
letter 420.