Canon 21
That no clergy should charge interest on anything lent.
It is also reasoned that the cleric who lent money should receive the same amount of money, and the one who gave things would receive as much as he gave.
Greek original
Ὁμοίως ἤρεσεν, ἵνα κληρικός, ἐὰν χρήματα δῷ ἐν χρήσει, τὰ χρήματα λάβῃ· ἐὰν δὲ εἶδος, ὅσον δέδωκε λάβῃ.[1]