Did Israel's weakness break God's covenant with Abraham?
No. The covenant God made with Abraham was not broken by Israel’s weaknesses, because it began with God and will end with God. The promises of Scripture likewise begin and end in God Himself. Israel’s weakness did not nullify what God purposed.
Les explains that everything begins and ends in and with God, especially when teaching the Old Testament covenants. When God made His covenant with Abraham, He did so in spite of all the weaknesses of the nation of Israel and the children of Abraham. The question is asked whether that broke the covenant, and the answer is no, because it began with God and will end with God. The same is true of all the promises of Scripture: they begin and they end in God Himself. This is set alongside Ephesians 1, where God’s purpose and good pleasure are according to His own will, and He is Sovereign and can do things as He sees fit.