Being truly happy or being truly joyful is being truly close to completeness. And being close to true completeness is being truly close to God. Now then, to get truly close to God is also to become compete as God.
Because in truth, only God is completely happy or only God is completely joyful because in truth the happiness of God or the joy of God makes God completely happy or complete joyful!
That is, the happiness or the joy of God is what completes and recompletes as always new and when one finds the happiness or the joy of God thus one is about to be complete as new!