Translation: Gileadi’s translation is clearer: “Look to Abraham, your father, to Sarah, who bore you. He was but one when I called him, but I blessed him by making him many.” The Today’s English Version translates this passage: “Think of your ancestor, Abraham, and of Sarah, from whom you are descended. When I called Abraham, he was childless, but I blessed him and gave him children; I made his descendants numerous.”
Isaiah is identifying Abraham and Sarah as the foundation of Israel’s lineage, reminding his listeners of Yahweh’s relationship to and covenant with Abraham. Abraham’s blessing was to be a father of nations.
Meaning for Jacob’s Audience: Isaiah’s message is clearly meant for Abraham’s literal descendants, a reminder of their heritage and covenant status. By extension, it also applies to others adopted into that covenant relationship with Yahweh. By birthright or by adoption, Jacob’s audience should see themselves as possessing the same heritage and covenant as Isaiah’s original listeners.