Origen

Some one may argue, (e. g. The Ebionites) that because Jesus kept the Passover with Jewish observances, we ought to do the same as followers of Christ, not remembering that Jesus was made under the Law, though not that He should leave under the Law (Gal. 4:4.) those who were under it, but should lead them out of it; how much less fitting then is it, that those who before were without the Law, should afterwards enter in? We celebrate spiritually the things which were carnally celebrated in the Law, keeping the Passover in the unleavened bread of sincerity and truth, (1 Cor. 5:8. John 6:53.) according to the will of the Lamb, who said, Except ye eat my flesh and drink my blood, ye shall not have life in you.