The verse is a summary of a principle found in what I refer to as the Patriarchal Formula. God's dealings with Israel depend upon the promises and calling God made with Abraham, Isaac, and Jacob.The covenant God made with Abraham (Gen 12:1-3, 7; 13:14-18; 15:1-21; 17:1-27; 22:1-19) He extended to/through Isaac (Gen 26:-15) and Jacob (Gen 28:10-15). The terms of the covenant became foundational for the manner in which Yahweh acted on behalf of Abraham and his descendants, Israel.When Israel cried out under the tyranny of Egypt's cruel taskmasters, God remembered His covenant with Abraham, Isaac, and Jacob (Exodus 2:24), a factor Moses reiterates in Deut 7:8by declaring Israel's deliverance from Egyptian bondage was because the Lord loved you and kept the oath which He scored to your forefathers. Exodus 6:8reveals Yahweh's promise to lead Israel into the Promised Land was based upon His covenant with the Patriarchs.The northern tribes, Israel, received a stay of impending destruction because of Yahweh's faithfulness to the covenant with Abraham, Isaac, and Jacob (2 Kings 13:22-23). The exile of both Israel and Judah was part of Yahweh's chastisement designed to bring Israel back to Him.Regarding Paul's words found in Romans 11, here is the full context: