This would be true of human beings, but not of an immortal, self existent, eternal invisible God, who has made Himself known through His Son and by His Spirit, all of whom are One God (Echad or a unity of being.)
This is much simpler when you stop trying to bring God down to our level of understanding, but let me try to give you a real world example of division in purpose, but unity in being.
You and I have minds which we understand to function by virtue of our brains. With our minds we think, we reason, we interpret reality based upon our perceptions, and our mind is very much an expression of our physical reality, yet it is exceptionally hard to accurately quantify and if anyone tells you that they have a full understanding of what thought is, they're just lying. Our mind is very much what we are, yet we are more than just that. We are thinking beings, but we are also emotional beings. We commonly accept that emotion is also a function of our brains as well as thought, and we can manipulate emotion physically with chemical stimulus, yet emotion remains difficult to quantify or calculate. Both these aspects of our being are required to make us more than a simple biological machine, but we still fall into the same category as orangutans and parakeets with this limited view of ourselves. We are also spiritual beings. We have a built in sense of mortality and eternity. We fear death, not so much as an animal survival instinct, but because we by nature fear what would come after death, a judgment of the virtue or wickedness of our lives. We connect to other people spiritually in ways that we would never connect to them mentally or emotionally. This is largely what separates us from the animal kingdom, but the point I'm trying to get to is that without one of the components of being a thinking creature, an emotional creature, and a spiritual creature, we cease to be truly human.
The scripture identifies our nature with that of God, in the sense that we were intended to reflect who He is, but miss the mark. We are our thoughts to some extent, and we are our emotions to some extent, and we are also our spirit (perhaps to a greater extent.) We are a tri-unity, three types of being which all remain one in the fullest sense of completion.
The scripture teaches us that God is Spirit, eternal, self existent, pure, holy, incorruptible, and most significantly infinite in degree (or simply non finite), or described as omniscient, omnipresent and omnipotent. The eternal is nothing that can be grasped by the finite, but the scripture tells us that the Eternal God chose to interact with His creation, to reveal Himself in scripture through angelic beings, through His Spirit by prophets and kings, and ultimately by His Son who is His exact likeness as represented within His creation. If the infinite is to be represented within the context of the finite He must take on some form and He did this in the person of His Son. The bible teaches this and the Son who is the True and Faithful witness confirms the Father in Himself. My mind can attest to my emotion and my spirit, yet all three remain what I am. The analogy isn't perfect in that we remain finite beings, while in God the infinite took on finite qualities (and appears to have done so forever,) yet the comparison remains valid in the context of our understanding of what ultimately can never be understood by us without the mind of God Himself.
I'm sure of two things: I don't have that mind and neither do you. If either of us did, we wouldn't be trying to convince one another of the obvious. From a mental perspective, its inconceivable to me that God would even bother with us, but from an emotional perspective I can receive the love that He's shown us and in some small and flawed way return it to Him in gratitude, praise, and joy. Where do you get that without seeing Him in His Son, in His suffering and His sacrifice, in His mercy and in His grace? Perhaps you don't see it at all, but I pray that you do and that you may know Him as redeemer, kinsman and friend. Amen
