In the synagogue the Torah is read aloud in a fixed annual cycle of fifty-four weekly portions (parashiyot), one each Shabbat morning, with certain adjacent portions doubled in ordinary years so the sequence fits the calendar. Each portion is named for a distinctive word near its opening and is paired with a haftarah, a reading from the Prophets. The cycle closes and restarts on Simchat Torah. Lech-Lecha ('Go forth', Genesis 12:1-17:27) begins the story of Israel's patriarchs with God's command to Abram to leave his land for a country he will be shown. It includes the covenant between the pieces, the birth of Ishmael to Hagar, and the covenant of circumcision that renames Abram and Sarai as Abraham and Sarah.
The covenant between the pieces (Genesis 15:9-21), in which Abram falls into a deep sleep and a smoking firepot and flaming torch pass between the halved carcasses of sacrificed animals, follows an ancient Near Eastern treaty-ratification form attested outside the Bible in which the parties to an oath would walk between divided animals, invoking a similar fate on themselves should they break the agreement; here, unusually, only the divine symbols pass through, read by commentators including Ramban as signalling that the covenant's fulfilment rests on God's commitment alone rather than requiring a matching oath from Abram. The birth of Ishmael to Hagar, Sarai's Egyptian handmaid, and the angel's promise to Hagar in the wilderness that he would father a great nation (Genesis 16:10-12), establishes a figure both Jewish and later Islamic tradition trace significant lineage through, though the traditions diverge sharply over which son, Isaac or Ishmael, carries the primary covenantal promise going forward.