God has no body

As, therefore, our understanding is unable of itself to behold God Himself as He is, it knows the Father of the world from the beauty of His works and the comeliness of His creatures.  God, therefore, is not to be thought of as being either a body or as existing in a body, but as an uncompounded intellectual nature, admitting within Himself no addition of any kind; so that He cannot be believed to have within him a greater and a less, but is such that He is in all parts Μονάς, and, so to speak, ῾Ενάς, and is the mind and source from which all intellectual nature or mind takes its beginning.

Origen
On First Principles, Book I
Chapter I

God is everywhere present and fills all things

Thou errest, O man, and art deceived; for from where is God afar off, when all things heavenly and earthly, and which are beyond this province of the universe, are known to God, are full of God?  Everywhere He is not only very near to us, but He is infused into us. Therefore once more look upon the sun:  it is fixed fast in the heaven, yet it is diffused over all lands equally; present everywhere, it is associated and mingled with all things; its brightness is never violated.  How much more God, who has made all things, and looks upon all things, from whom there can be nothing secret, is present in the darkness, is present in our thoughts, as if in the deep darkness.  Not only do we act in Him, but also, I had almost said, we live with Him.

Minucius Felix
Octavius
Chapter XXXII

The Trinity is one God in substance but three persons

But keeping this prescriptive rule inviolate, still some opportunity must be given for reviewing (the statements of heretics), with a view to the instruction and protection of divers persons; were it only that it may not seem that each perversion of the truth is condemned without examination, and simply prejudged; especially in the case of this heresy, which supposes itself to possess the pure truth, in thinking that one cannot believe in One Only God in any other way than by saying that the Father, the Son, and the Holy Ghost are the very selfsame Person. As if in this way also one were not All, in that All are of One, by unity (that is) of substance; while the mystery of the dispensation is still guarded, which distributes the Unity into a Trinity, placing in their order the three Persons—the Father, the Son, and the Holy Ghost: three, however, not in condition, but in degree; not in substance, but in form; not in power, but in aspect; yet of one substance, and of one condition, and of one power, inasmuch as He is one God, from whom these degrees and forms and aspects are reckoned, under the name of the Father, and of the Son, and of the Holy Ghost. How they are susceptible of number without division, will be shown as our treatise proceeds.

Tertullian
Against Praxeas
Chapter II

Christ did not cease to be God when he became man

Why, I want to know, was it of so much importance, that Christ should, when perfectly aware what He really was, exhibit Himself as being that which He was not? You cannot express any apprehension that, if He had been born and truly clothed Himself with man’s nature, He would have ceased to be God, losing what He was, while becoming what He was not. For God is in no danger of losing His own state and condition.

Tertullian 
On the Flesh of Christ
Chapter III

Some of the Gnostics teach that God the Father is also a man

Some there are who have imagined that another origin must be found for the title “Son of man;” for they have had the presumption to call the Father Himself Man, by reason of the profound mystery of this title: so that what can you hope for more ample concerning faith in that God, with whom you are now yourself on a par? Such conceits are constantly cropping out amongst them, from the redundance of their mother’s seed. And so it happens that the doctrines which have grown up amongst the Valentinians have already extended their rank growth to the woods of the Gnostics.

Tertullian
Against the Valentinians
Chapter XXXIX

We are made gods by grace and not by any property of our own

Well, then, you say, we ourselves at that rate possess nothing of God. But indeed we do, and shall continue to do—only it is from Him that we receive it, and not from ourselves. For we shall be even gods, if we, shall deserve to be among those of whom He declared, “I have said, Ye are gods,” and, “God standeth in the congregation of the gods.” But this comes of His own grace, not from any property in us, because it is He alone who can make gods.

Tertullian
Against Hermogenes
Chapter V

There is only one God and Father of all

For “although there be that are called gods” in name, “whether in heaven or in earth, yet to us there is but one God the Father, of whom are all things;” whence the greater reason why, in our view, that which is the property of God ought to be regarded as pertaining to God alone, and why (as I have already said) that should cease to be such a property, when it is shared by another being. Now, since He is God, it must necessarily be a unique mark of this quality, that it be confined to One. Else, what will be unique and singular, if that is not which has nothing equal to it? What will be principal, if that is not which is above all things, before all things, and from which all things proceed? By possessing these He is God alone, and by His sole possession of them He is One.  If another also shared in the possession, there would then be as many gods as there were possessors of these attributes of God.

Tertullian
Against Hermogenes
Chapter IV