Read Romans 9:30-33
The Jews had a worthy goal: to honor God. But they tried to achieve it the wrong way: by rigid and painstaking obedience to the law. Thus, some of them became more dedicated to the law than to God. They thought that if they kept the law, God would have to accept them as His people. But God cannot be controlled. The Jews did not see that their Scriptures, the Old Testament, taught that salvation depended on faith, not on human effort (Genesis 15).
The rock they stumbled over was Jesus. The Jews did not believe in Him, because He didn’t meet their expectations for the Messiah. Some people still stumble over Christ because salvation by faith doesn’t make sense to them. They think they must earn their way to God, or perhaps God will simply overlook their sins. Others stumble over Christ because His values are the opposite of the world’s. He asks for humility, and many are unwilling to humble themselves before Him. He requires obedience, and many refuse to put their wills at His disposal.
Sometimes we are like these people, trying to get right with God by keeping His laws. We may think that attending church, doing church work, giving offerings, and being nice will be enough. After all, we’ve played by the rules, haven’t we? But Paul’s words sting: this approach never succeeds. Paul explains that God’s plan is not for those who try to earn His favor by being good; it is for those who realize that they can never be good enough and so must depend on Christ. We can be saved only by putting our faith in what Jesus Christ has done. If we do that, we will never be disappointed.