Genesis 12:1 to 17:27, Isaiah 40:27 to 41:16
Notice that Avraham's covenant of circumcision is for not just his family, but for all his household's servants as well.
Verse 12:3 mixes plural ("those who bless you") and singular ("he who curses you"). God expected more prople to bless Avram than curse him. (Similarly, according to one legend only Nimrod cursed Avram, after Avram proved Nimrod was not a deity.)
The tremendous extent of Avram's trust in God is visible in how he left Charan. The practical plan would be to travel with a few servants, and upon reaching the destination to send for the rest of his family and household. But Avram was so confident that God would provide a good place to live that he set forth with his entire household.
The phrase "and the souls which they had made in Charan" (verse 12:5) hints that Avram and Sarai had made converts to the worship of Adonai before leaving Charan. According to Toldot Yitzchak, Avram's many stops along the journey were at places where God asked him to make more converts.
Toldot Yitzchak also attributes Avram's departure from Canaan in verse 12:10 to the effects of Avram's proselytizing: this was the world's first famine, and the Canannites said their gods were punishing them for listening to Avram and abandoing idol worship.
Rashi continues the story the Toldot Yitzchak began, by claiming that Lot was captured by the four kings because he looked like Avram, and the four kings were planning on returning their people to idolatry by publicly mistreating Lot (i.e., demonstrating that Adonai was not saving "Avram" from the kings).
In verse 12:18 Pharaoh blames Avram, not Sarai, for deceiving him. Sarai had been silent, and had not mentioned her marriage, whereas Avram purposefully said Sarai was only (see verse 20:12) his sister.
In verse 13:3 the phrase "his journeys" means Avram stopped at the same inns as he did during the trip to Egypt. He was wealthy and could afford better, but did not desire to spend his money on luxuries. Moreover, while traveling to Egypt he had merely promised to pay the innkeepers because he was worried that displaying money would invite trouble; now he paid off his debts. Thus explain Rebbi Yosef Shaul Natanzon and Rashi.
Verse 13:14 tells us that God did not speak to Avram while Lot was with Avram.
Technically, a Hebrew (Eevree) would be any descendent of Ever (verse 11:14-17). The word Eevree also means "one who crosses over", and is applied to Avram and his descendants because they crossed over out of Charan ("crossroads"), and out of idolatry.
Lot was Avram's brother's son, and corrupted by the evil of Sodom. Yet Avram thinks of Lot as a brother (verses 13:8 and 14:14).
The word vayarek in verse 14:14 can be translated as either "he led" or "he emptied". R' Bechaye taught that Avraham sent home all of his 318 men who had sinned and would not receive God's assistance in the battle. When everyone but Eliezer left, Avram noticed that the numberical value of Eliezer's name is 318, and trusted that God was with them because what had been made rek (empty) was again filled.
A Midrash claims Malki-Tzedek was Shem the son of Noach.
Verse 15:15 implies that Avram's father, Terach, had repented before his death.
Because the covenant established in chapter 15 is unconditional, Avram is only a spectator while God passes between the animal pieces.