What is meant by the independence of God?

The independence of God is his absolutely necessary being and sovereignty sourced wholly in himself.

(1) God exists necessarily not by an act of his will (i.e., he is not self-caused), but by the dictates of his own nature (i.e., he is uncaused). He cannot be other than what he is.

(2) God is totally non-contingent on anything external to himself with respect both to his existence and his activities—impassibility. God cannot be affected by the free acts of his creatures, because, while free, these actions are not free from external causation and therefore are not truly independent.