Theodoret of Cyrus: Christ our Substitute

God the Word, therefore, in taking on our nature, kept it free of all sin and erased the record of our debts incurred by us in it to our detriment. By allowing it to be attached to the cross, he paid the debt of us all; and by fulfilling the Law he brought it to an end, useful though it proved of old to Jews alone, but in no way suitable for us. Instead, he gave us the evangelical decrees, promising us salvation through observance of them.

- Theodoret of Cyrus (around A.D. 393 to around A.D. 457), Commentary on the Letter to the Colossians, Chapter 2, in Theodoret of Cyrus, Commentary on the Letters of St. Paul, Volume 2, p. 94 (2001), Robert C. Hill translator.