Azymes

why use unleavened bread if Many of the Fathers condemn it?

It is important to know that those who offer unleavened bread, offer dead flesh, and not living. For the leaven becomes like a soul to the dough, and the salt like the mind.

-St John of Damascus on Azymes

no Church received the custom of eating or offering the semolina of unleavened bread; since neither did Christ Himself eat the legal Passover at the time of His passion, listen to John the Evangelist saying: "Now before the feast of the Passover, when Jesus knew that His hour had come that He should depart out of this world unto the Father,... 1 and supper being ended, the devil having now put into the heart of Judas Iscariot, Simon's son, to betray Him; (St Athanasius on Azymes)

"Therefore, the four evangelists say that the Lord delivered perfect bread in the holy mysteries and not unleavened bread." And later: "so that it may be believed that He had a perfect body from the Holy Virgin; I mean animate and intelligent." The emphasis on "perfect" bread and body implies leavened bread and a fully human Christ, respectively. (Athanasius, from the same)

"and the unleavened bread alone without leaven is dead and is not life-giving bread." (Athanasius, from the same)

He said that Christ took bread, and not unleavened bread; for it was no longer, since it was then the fifth day; the moon was still the thirteenth, and there was no unleavened bread, because it had not yet been made; (Athanasius, from the same)