Man will become higher than the angels

For there is the one Son, who accomplished His Father’s will; and one human race also in which the mysteries of God are wrought, “which the angels desire to look into;” and they are not able to search out the wisdom of God, by means of which His handiwork, confirmed and incorporated with His Son, is brought to perfection; that His offspring, the First-begotten Word, should descend to the creature, that is, to what had been moulded (plasma), and that it should be contained by Him; and, on the other hand, the creature should contain the Word, and ascend to Him, passing beyond the angels, and be made after the image and likeness of God.

Irenaeus of Lyons
Against Heresies, Book V
Chapter XXXVI

The new flesh of the resurrection is the same as the old flesh

He promised to drink of the fruit of the vine with His disciples, thus indicating both these points: the inheritance of the earth in which the new fruit of the vine is drunk, and the resurrection of His disciples in the flesh. For the new flesh which rises again is the same which also received the new cup.

Irenaeus of Lyons
Against Heresies, Book V
Chapter XXXIII

No soul sleep before the resurrection

For as the Lord “went away in the midst of the shadow of death,” where the souls of the dead were, yet afterwards arose in the body, and after the resurrection was taken up [into heaven], it is manifest that the souls of His disciples also, upon whose account the Lord underwent these things, shall go away into the invisible place allotted to them by God, and there remain until the resurrection, awaiting that event; then receiving their bodies, and rising in their entirety, that is bodily, just as the Lord arose, they shall come thus into the presence of God.

Irenaeus of Lyons
Against Heresies, Book V
Chapter XXXII

 

The number of the beast: 666, not 616

I do not know how it is that some have erred following the ordinary mode of speech, and have vitiated the middle number in the name, deducting the amount of fifty from it, so that instead of six decads they will have it that there is but one. [I am inclined to think that this occurred through the fault of the copyists, as is wont to happen, since numbers also are expressed by letters; so that the Greek letter which expresses the number sixty was easily expanded into the letter Iota of the Greeks.]

But, knowing the sure number declared by Scripture, that is, six hundred sixty and six…

Irenaeus of Lyons
Against Heresies, Book V
Chapter XXX

 

Men bring Hell on themselves. It’s not a punishment.

Now, good things are eternal and without end with God, and therefore the loss of these is also eternal and never-ending. It is in this matter just as occurs in the case of a flood of light: those who have blinded themselves, or have been blinded by others, are for ever deprived of the enjoyment of light. It is not, [however], that the light has inflicted upon them the penalty of blindness, but it is that the blindness itself has brought calamity upon them: and therefore the Lord declared, “He that believeth in Me is not condemned,” that is, is not separated from God, for he is united to God through faith.

Irenaeus of Lyons
Against Heresies, Book V
Chapter XXVII

Man is saved by grace

And justly indeed is he led captive, who had led men unjustly into bondage; while man, who had been led captive in times past, was rescued from the grasp of his possessor, according to the tender mercy of God the Father, who had compassion on His own handiwork, and gave to it salvation, restoring it by means of the Word—that is, by Christ—in order that man might learn by actual proof that he receives incorruptibility not of himself, but by the free gift of God.

Irenaeus of Lyons
Against Heresies, Book V
Chapter XXI

 

Through the “person” of the Spirit we see

These things, therefore, He recapitulated in Himself: by uniting man to the Spirit, and causing the Spirit to dwell in man, He is Himself made the head of the Spirit, and gives the Spirit to be the head of man: for through Him (the Spirit) we see, and hear, and speak.

Irenaeus of Lyons
Against Heresies, Book V
Chapter XX