Over 4,000 years ago, God promised Abraham that through one of his descendants (seed) all the world would be blessed (Genesis 12:2-3; Genesis 12:7 ; Genesis 13:15; Genesis 24:7).  The Jews thought that the blessing was going to come through each of them because they were all descended from Abraham.  But Paul knew his Hebrew very well.  The word ‘seed’ is not plural but singular.  God’s primary promise of blessing was not about many devout Jews, but about one person – Jesus Christ.  And Abraham looked forward to the day when one person would fulfil all of God’s promises.  Jesus said, “Your father Abraham rejoiced at the thought of seeing my day; he saw it and was glad” (John 8:56).
 
The promises of blessing to those who believe God’s Word were given to Abraham over 400 years before God gave the law to Moses.  But that law could never undo God’s promise about the Lord Jesus Christ.  So when false teachers were trying to get new Christians to conform to the Jewish law, Paul said that they did not need to do so, because the law was only a temporary matter until Christ came (Galatians 3:24).  

That is why God is pleased to bless Jews and Gentiles who trust in Jesus.  The value of the law is to demonstrate that we have all sinned.  The value of the cross is to demonstrate that all who believe that Christ died for their sins are freed from sin’s curse and can inherit the blessing given to Abraham.  Disciples of Jesus have grasped hold of God’s original promise of blessing to Abraham; and that applies to Jews and Gentiles alike (Galatians 3:26-29).
 
It is hard for some people to understand that all God’s promises are completed in the Lord Jesus Christ (2 Corinthians 1:20).  Often, people think that they have to go on a journey to find God, but He has already revealed Himself in Jesus Christ.  Others think that they should pick the best bits out of different religions and try to find God that way.  But God’s ancient promise holds good.  As Peter said, “Salvation is found in no one else, for there is no other name under heaven given to mankind by which we must be saved.” (Acts 4:12).  In the same way that Paul had to keep on emphasizing the need to trust in Christ alone, so we too have a responsibility to tell our friends and colleagues.