God desired to share the same covenant relationship with the children of Israel at Sinai that He shared with Abraham. In fact, similarities exist between God’s words to Abraham in Genesis 12:1-3 and His words to Moses in Exodus 19. In both cases, God emphasizes what He will do for His people. He does not ask the Israelites to promise to do anything to earn His blessings; instead, they are to obey as a response to those blessings. The Hebrew word translated “to obey” in Exodus 19:5 literally means “to hear.” God’s words do not imply righteousness by works. On the contrary, He wanted Israel to have the same faith that characterized Abraham’s response to His promises (at least most of the time!).
If the covenant relationship God offered to Israel on Sinai is similar to the one given to Abraham, why does Paul identify Mount Sinai with the negative experience of Hagar? Exod. 19:7-25; Heb. 8:6-7.
The covenant at Sinai was intended to point out the sinfulness of humanity and the remedy of God’s abundant grace, which was typified in the sanctuary services. The problem with the Sinai covenant was not on God’s part but rather with the faulty promises of the people (Heb. 8:6). Instead of responding to God’s promises in humility and faith, the Israelites responded with self-confidence. “ ‘All that the LORD hath spoken we will do’ ” (Exod. 19:8). After living as slaves in Egypt for more than four hundred years, they had no true concept of God’s majesty nor the extent of their own sinfulness. In the same way that Abraham and Sarah tried to help God fulfill His promises, the Israelites sought to turn God’s covenant of grace into a covenant of works. Hagar symbolizes Sinai in that both reveal human attempts at salvation by works.
Paul is not claiming that the law given at Sinai was evil or abolished. He is concerned with the Galatians’ legalistic misapprehension of the law. “Instead of serving to convict them of the absolute impossibility of pleasing God by law-keeping, the law fostered in them a deeply entrenched determination to depend on personal resources in order to please God. Thus the law did not serve the purposes of grace in leading the Judaizers to Christ. Instead, it closed them off from Christ.” — O. Palmer Robertson, The Christ of the Covenants (Phillipsburg, N.J.: Presbyterian and Reformed Publishing Co., 1980), p. 181.
Source: Daily Sabbath School Lessons