The Covenant And The Law
Although Abraham is the father of the nation of Israel, the covenant made with Abram was to bless all the families of the earth (Genesis 12:3). Paul tells us in Gal. 3:17 that this covenant was "confirmed before of God in Christ." So, this covenant was not just a promise of a land for Israel; it was a promise of eternal life for those who believe. Romans 4:3 says, For what saith the scripture? Abraham believed God, and it was counted unto him for righteousness. To prove that this is a spiritual covenant, Paul goes on in Romans 4:5 But to him that worketh not, but believeth on him that justifieth the ungodly, his faith is counted for righteousness.
This covenant (promise) was made before the law, which rejects the law for salvation. Salvation is by promise, not by law (works). Paul uses an allegory to show this in Gal. 4:23 But he [who was] of the bondwoman was born after the flesh; but he of the freewoman [was] by promise. The difference is "after the flesh" and "by promise."
If you are saved "after the flesh," then you are not really saved. If you are saved "by promise," then you are truly saved. These are not my words but God's words.
This is true, because the promise was made to Abram 430 years before the law was given to Israel through Moses, so we know that Abram was saved by grace through faith and not by works. The law does not and cannot make void the promise that was 430 years before it.
Galatians 3:18 tells us that, if the inheritance (salvation) is of the law (of the flesh), then it is not of promise. Conclusion: "but God gave it to Abraham by promise." It is blessed to be saved by grace through faith without the deeds of the law. Rom. 3:28 Therefore we conclude that a man is justified by faith without the deeds of the law.