How does God reveal himself in the Old Testament?
God shows himself in the Old Testament as God, who created the world out of love and remains faithful to men even when they have fallen away from him into sin.
God makes it possible to experience him in history: With Noah he establishes a covenant to save all living things. He calls Abraham so as to make him “the father of a multitude of nations” (Gen 17:5b) and to bless “all the families of the earth” in him (Gen 12:3b). The people Israel, sprung from Abraham, becomes his special possession. To Moses he introduces himself by name. His mysterious name Yhwh, usually transcribed Yahweh, means “I am who I am” (Ex 3:14). He frees Israel from slavery in Egypt, establishes a covenant with them on Sinai, and through Moses gives them the Law. Again and again, God sends prophets to his people to call them to conversion and to the renewal of the covenant. The prophets proclaim that God will establish a new and everlasting covenant, which will bring about a radical renewal and definitive redemption. This covenant will be open to all human beings.
What does God show us about himself when he sends his Son to us?
God shows us in Jesus Christ the full depth of his merciful love.
Through Jesus Christ the invisible God becomes visible. He becomes a man like us. This shows us how far God’s love goes: He bears our whole burden. He walks every path with us. He is there in our abandonment, our sufferings, our fear of death. He is there when we can go no farther, so as to open up for us the door leading into life.
CCC section (54-65)