The speaker considers the human agent is the true human person. The Psalm probably originated in the safe, comfortable, royal court and celebrated a royal person's power and authority. At the centre of the Psalm is this affirmation of human power and authority. At the Psalm's boundaries are affirmations of praise to God. Either, taken alone, miss the point.
Human power is always bounded and surrounded by divine praise.
Such loyalty must be directed only to God. The early Christian writers, rather than speculate on the nature of the Godhead, show how the apostles focus on the Trinity's action in the life of believing disciples. The formation of an alternative community is under way. Christian discipleship is a response to the command of God. It is truly a human work.