When the Scripture states that man was made in the image of God, we dare not add to that statement an idea from our own head and make it mean "in the exact image." To do so is to make man a replica of God, and that is to lose the unicity of God and end with no God at all. It is to break down the wall, infinitely high, that separates That-which-is-God from that-which-is-not-God. To think of creature and Creator as alike in essential being is to rob God of most of His attributes and reduce Him to the status of a creature. It is, for instance, to rob Him of His infinitude: there cannot be two unlimited substances in the universe. It is to take away His sovereignty: there cannot be two absolutely free beings in the universe, for sooner or later two completely free wills must collide. These attributes, to mention no more, require that there be but one to whom they belong.
Source: The Knowledge of the Holy by A. W. Tozer