Resurrected bodies are constructed from the very same elements

But if to any one it appears sheer nonsense that the body which has mouldered away, and been dissolved, and reduced to nothing, should be reconstructed, we certainly cannot with any reason be accused of wickedness with reference to those that believe not, but only of folly;

…for nothing hinders, according to Pythagoras and Plato, that when the dissolution of bodies takes place, they should, from the very same elements of which they were constructed at first, be constructed again. But let us defer the discourse concerning the resurrection.

Athenagoras of Athens
A Plea for the Christians
Chapter XXXVI

Abortion recognized as murder

And when we say that those women who use drugs to bring on abortion commit murder, and will have to give an account to God for the abortion, on what principle should we commit murder? For it does not belong to the same person to regard the very fetus in the womb as a created being, and therefore an object of God’s care, and when it has passed into life, to kill it;

Athenagoras of Athens
A Plea for the Christians
Chapter XXXV

Traditions of celibacy in the early Church

For as the husbandman throwing the seed into the ground awaits the harvest, not sowing more upon it, so to us the procreation of children is the measure of our indulgence in appetite. Nay, you would find many among us, both men and women, growing old unmarried, in hope of living in closer communion with God.

Athenagoras of Athens
A Plea for the Christians
Chapter XXXIII

Father, Son and Holy Spirit are one essence

For, as we acknowledge a God, and a Son his Logos, and a Holy Spirit, united in essence,—the Father, the Son, the Spirit, because the Son is the Intelligence, Reason, Wisdom of the Father, and the Spirit an effluence, as light from fire; so also do we apprehend the existence of other powers, which exercise dominion about matter, and by means of it, and one in particular, which is hostile to God:

Athenagoras of Athens
A Plea for the Christians
Chapter XXIV

God is immaterial spirit

But grant that they acknowledge the same. What then? Because the multitude, who cannot distinguish between matter and God, or see how great is the interval which lies between them, pray to idols made of matter, are we therefore, who do distinguish and separate the uncreated and the created, that which is and that which is not, that which is apprehended by the understanding and that which is perceived by the senses, and who give the fitting name to each of them,—are we to come and worship images?

Athenagoras of Athens
A Plea for the Christians
Chapter XV

Oneness of the Father, Son and Spirit

Are, then, those who consider life to be comprised in this, “Let us eat and drink, for to-morrow we die,” and who regard death as a deep sleep and forgetfulness (“sleep and death, twin brothers”), to be accounted pious; while men who reckon the present life of very small worth indeed, and who are conducted to the future life by this one thing alone, that they know God and His Logos, what is the oneness of the Son with the Father, what the communion of the Father with the Son, what is the Spirit, what is the unity of these three, the Spirit, the Son, the Father, and their distinction in unity;

Athenagoras of Athens
A Plea for the Christians
Chapter XII

Only God creates ex nihilo

For even a human artist, when he gets material from some one, makes of it what he pleases. But the power of God is manifested in this, that out of things that are not He makes whatever He pleases; just as the bestowal of life and motion is the prerogative of no other than God alone. For even man makes indeed an image, but reason and breath, or feeling, he cannot give to what he has made. But God has this property in excess of what man can do, in that He makes a work, endowed with reason, life, sensation. As, therefore, in all these respects God is more powerful than man, so also in this; that out of things that are not He creates and has created things that are, and whatever He pleases, as He pleases.

Theophilus of Antioch
To Autolycus, Book II
Chapter IV

Christ the perfect Intelligence of God. God in God.

With regard to Christ, the law and the prophets and the evangelists have proclaimed that He was born of a virgin, that He suffered upon a beam of wood, and that He appeared from the dead; that He also ascended to the heavens, and was glorified by the Father, and is the Eternal King; that He is the perfect Intelligence, the Word of God, who was begotten before the light; that He was the Founder of the universe, along with it (light), and the Maker of man; that He is All in all: Patriarch among the patriarchs; Law in the laws; Chief Priest among priests; Ruler among kings; the Prophet among prophets; the Angel among angels; the Man among men; Son in the Father; God in God; King to all eternity. For it is He who sailed [in the ark] along with Noah, and who guided Abraham; who was bound along with Isaac, and was a Wanderer with Jacob; the Shepherd of those who are saved, and the Bridegroom of the Church; the Chief also of the cherubim, the Prince of the angelic powers; God of God; Son of the Father; Jesus Christ; King for ever and ever. Amen.

Irenaeus of Lyons
Lost Writings
Fragment LIII

Christ is God and comes from within God as the first begotten

The sacred books acknowledge with regard to Christ, that as He is the Son of man, so is the same Being not a [mere] man; and as He is flesh, so is He also spirit, and the Word of God, and God. And as He was born of Mary in the last times, so did He also proceed from God as the First-begotten of every creature; and as He hungered, so did He satisfy [others]; and as He thirsted, so did He of old cause the Jews to drink, for the “Rock was Christ” Himself: thus does Jesus now give to His believing people power to drink spiritual waters, which spring up to life eternal.

…And as He was the servant of God, so is He the Son of God, and Lord of the universe.

Irenaeus of Lyons
Lost Writings
Fragment LII

The soul is created at the time of the body and does not preexist it

We are convinced that there exist [so to speak] two men in each one of us. The one is confessedly a hidden thing, while the other stands apparent; one is corporeal, the other spiritual; although the generation of both may be compared to that of twins. For both are revealed to the world as but one, for the soul was not anterior to the body in its essence; nor, in regard to its formation, did the body precede the soul: but both these were produced at one time; and their nourishment consists in purity and sweetness.

Irenaeus of Lyons
Lost Writings
Fragment XLIX