Genesis ch. 17: 1-2 and 4 When Abraham was 99 years old, the Lord appeared to him and said, " I am God Almighty; walk before me and be blameless. Then I will make my covenant between me and you and will greatly increase your numbers. As for me, this is covenant with you. You will be the father of many nations.
Abraham is asked to be blameless and faithful to God. In return, God says he would make him the father of many nations and that he would make a covenant with God and Abraham p. After the covenant his numbers would increase, but this would only be fulfilled if they keep the covenant with God forever.
Exodus ch. 6:1 and ch. 7 3-5 Then the Lord said to Moses, " Now you will see what I will do to Pharaoh. Because of my mighty hand he will let them go; because of my mighty hand he will drive them out of his country. But I will harden Pharaoh's heart, and though I multiply my signs and wonders in Egypt, he will not listen to you.
Now, Moses was doubting his speech and himself, but God says that he has made Moses like God to Pharaoh. He says that he will save his people and show these wonders and signs in Egypt. It also shows how much love God has for his people and the tremendous power he has.