An Argument that Cyril Used Irenaeus's Prescriptions Against Heresies Which Was Also Used by Tertullian to Make His Prescription Against Heresies

It is generally acknowledged that Cyril derived almost all his knowledge of the early heresies from Irenaeus.  He mentions one work in particular that he used - Irenaeus's Prescriptions Against the Heresies.  Here are some examples of Cyril - in reference to 'the heresies' and 'heretics' - drawing from a Greek text of Irenaeus which may have influenced Tertullian writing the Prescription Against Heresies in Latin.  Cyril declares at the end of the Fifth Catechetical Lecture:

Guard them with reverence, lest per chance the enemy despoil any who have grown slack; or lest some heretic pervert any of the truths delivered to you. For faith is like putting money into the bank, even as we have now done; but from you God requires the accounts of the deposit. I charge you, as the Apostle says, before God, who quickens all things, and Christ Jesus, who before Pontius Pilate witnessed the good confession, that you keep this faith which is committed to you, without spot, until the appearing of our Lord Jesus Christ. A treasure of life has now been committed to you, and the Master demands the deposit at His appearing, which in His own times He shall show, Who is the blessed and only Potentate, the King of kings, and Lord of lords; Who only has immortality, dwelling in light which no man can approach unto; Whom no man has seen nor can see. To Whom be glory, honour, and power 1 Timothy 6:15-16 forever and ever amen.  

This is taken almost verbatim from the interpretation in Tertullian's Prescription or - as we suggest - its original Greek source - viz. Irenaeus's Prescription Against Heresies:

But, as we have said, the same madness is seen when they allow indeed that the Apostles were not ignorant of anything nor preached different doctrines, yet will have it that they did not reveal all things to all persons, but committed some things openly to all, and others secretly to a few; basing this assertion on the fact that Paul used this expression to Timothy, "O Timothy, guard the deposit" and again, "Keep the good deposit." What was this "deposit" of so secret a nature as to be reckoned to belong to another doctrine ? Was it a part of that charge of which he says, "This charge I commit to thee, son Timothy" And likewise of that commandment of which he says, "I charge thee before GOD Who quickeneth all things, and Jesus Christ Who witnessed before Pontius Pilate a good confession, that thou observe the commandment " ? What commandment, now, and what charge ? From the context it may be gathered not that something is obscurely hinted at in this phrase concerning a more hidden doctrine, but rather that he was commanded not to admit anything beyond that which he had heard from Paul himself, openly too, I take it—"before many witnesses" are his words.