Aristotle conceives of a cosmos, a hierarchically ordered world in which things have their places. Human being is the highest animal of all. The highest being of all is God, the unmoved mover of the entire world. God is pure actuality and contains no matter. God is pure thought.
In the Physics, Aristotle argues that there must be a highest being.
He argues that if there is movement in the world, there must be an original source of that movement.
The original source of movement cannot itself be moved. If it were moving, it, too, would require a cause to move it.
There is thus one, primary, unmoved mover.
Aristotle’s God is not like the God of the Jews, Christians, or Muslims.
Aristotle’s God has no moral virtues. It is not generous or loving or just. To be moral implies some sort of lack.
God lacks nothing. Hence, God cannot be moral.
Aristotle’s God is pure thinking, which is the highest activity.
Aristotle’s views on these matters have been debated for centuries. The basic takeaway is Aristotle's views give affirmation to his conviction that the world is an intelligible cosmos. By having a first principle, an unmoved mover, it ultimately makes sense.
sources used:
David Roochnik, Introduction to Greek Philosophy
Robert Bartlett Masters of Greek Thought: Socrates, Plato, Aristole