Why does the Old Testament forbid images of God, and why do we Christians no longer keep that commandment?

In order to protect the mystery of God and to set the people of Israel apart from the idolatrous practices of the pagans, the First Commandment said, "You shall not make for yourself a graven image" (Ex 20:4). However, since God himself acquired a human face in Jesus Christ, the prohibition against images was repealed in Christianity; in the Eastern Church, icons are even regarded as sacred. [2129-2132,2141] The knowledge of the patriarchs of Israel that God surpasses everything and is much greater than anything in the world lives on today in Judaism as in Islam, where no image of God is or ever was allowed. In Christianity, in light of Christ’s life on earth, the prohibition against images was mitigated from the fourth century on and was abolished at the Second Council of Nicaea (787). By his Incarnation, God is no longer absolutely unimaginable; after Jesus we can picture what he is like: “He who has seen me has seen the Father” (Jn 14:9).