What is God like? How can we know him?
One place to start is with God's aseity. Aseity is a fancy word that just means "without need," or "underived." Someone that has aseity exists out of nothing.
God has aseity. In Moses encounter with the burning bush two instances of it appear. First he sees a flaming bush. It is on fire, but the bush is not being consumed. In fact the bush seems to be completely unaffected. "And the angel of the Lord appeared to him in a flame of fire out of the midst of a bush. He looked, and behold, the bush was burning, yet it was not consumed." (Exodus 3:2-3). The "angel of the Lord" is often a synonym for the preincarnate Christ.
God converses with Moses from the bush. Eventually Moses asks the Voice to identify himself. God responds, "I am who I am.”...“Say this to the people of Israel, ‘I am has sent me to you" (Exodus 3:14).
Here are two demonstrations of Aseity. The first is the "angel of the Lord" represented by a flame that does not need fuel. "The bush was burning, yet it was not consumed." In other words, the flame burned from an infinite supply of energy arising from within itself. Its energy is underived, that is, it does not depend upon something outside of itself. The flame is completely self-sufficient. It will burn forever on its self.
The second demonstration of Aseity is God's Name, "I Am who I am," or just "I am." It means that God is the self existent one who has always been and will always be. He is dependent upon nothing. he needs nothing. He is self-sufficient within himself.
By contrast, everything in the universe is dependent. It all derives from God. Creation has a beginning and an end, a source outside of itself. But God dwells outside of time. He has no begining. He has no end. He is derived from nothing. He just is. He needs nothing. He is "I am who I am."
Why is this important to us? There are at least three reasons. First, God's aseity means that he did not create to fulfill some inner need in himself. He has no needs, no voids, no unfulfilled longings, no incompletions. So why did he create? He created us for his glory. "Bring my sons from afar and my daughters from the end of the earth, everyone who is called by my name, whom I created for my glory" (Isaiah 43:6-7).
Second, if God has aseity he must be infinitely and unchangeably happy. In fact, he is utterly filled up with joy in the presence of the Trinitarian community, a joy that never slacks, never diminishes, nor ever needs to be replenished. That is why "joy" is the second fruit of the Spirit (Gal 5:22). The Holy Spirit is undiminished, exuberant joy. The more we dwell in him, live in him, the more joy we also will experience. That is why Heaven will be a realm of "Joy inexpressible and full of glory" (1 Pet. 1:8). God will be there.
Third, God's aseity means that need does not motivate his love. There is not an iota of selfishness in God. This is impossible for us to comprehend. We do nothing without need. But God sent His Son to die on a Roman Cross when he had no needs, when our salvation could add nothing to his happiness. How can we understand such selflessness?
All of this Paul deftly summed up in his immortal conclusion to Romans 11. "Who has given a gift to him that he might be repaid?” For from him and through him and to him are all things. To him be glory forever. Amen." (Romans 11:35-36).
Let us bow down and worship the God whose flame needs no external fuel , the One who calls himself "I am that I am."