He is the image of the invisible God. Col. 1:15
The sum is this – that God in himself, that is, in his naked majesty, is invisible, and that not to the eyes of the body merely, but also to the understandings of men, and that he is revealed to us in Christ alone, that we may behold him as in a mirror. For in Christ he shows us his righteousness, goodness, wisdom, power, in short, his entire self. We must, therefore, beware of seeking him (God) elsewhere, for everything that would set itself off as a representation of God, apart from Christ, will be an idol.
—from Calvin’s Commentary