Genesis 12 - God promises to bless Abraham and give him children, and calls him to go to Canaan. He goes, by faith, lives as a pilgrim/refugee, and continues down to Egypt since there is a famine in Canaan. He pretends Sarah is his sister, so they don't kill him. Pharaoh turns out to be righteous, though, and treats her honorably, and him with needed rebuke.
13 - Abram goes back to Canaan, separates from Lot who goes to nice-looking Sodom. God promises Abram the land again. He sets up altars to God.
14 - Lot is taken captive, as a citizen of Sodom; Abram rescues him, and is blessed by Melchizedek, king of Jerusalem
15 - God again promises Abraham that he will have children. Abraham believes, and God considers him righteous for that belief. But Abraham still wants to know it can be. God performs a blood ritual, giving Abraham a self-maledictory oath, and a prophecy about Israel's future in and out of Egypt.
16 - After 10 years Abraham's faith wavers, and he tries to make the promise come true through Hagar. This causes strife in Abraham's family, as Ishmael is born. God promises Hagar that he will become a great nation, too, but he will be hostile to everybody.
17 - God gives a more lasting sign of His covenant promise to bless Abraham: circumcision. Thus, Isaac will be conceived and born in circumcision, unlike Ishmael, who is now 13. Abraham is 99; Sarah is 90.