In this passage, God give Abraham the promise that many nations will come from him. He establishes and everlasting covenant and gives Abraham the sign of circumcision to set apart everyone who is a part of this covenant. In order to keep this covenant, Abraham must “walk before God” and “be blameless.” From the very beginning, this covenant was impossible to keep in the flesh. How can any sinful human being walk before God in a blameless way? We know from Romans that “all have sinned and fall short of the glory of God.”
Thanks be to God that, through the promised offspring of Abraham, he sent Jesus–the God-man–to live the life we could not live and die the death we deserved. Now, in Christ, every person who places their trust in Him, can walk blameless before God in His righteousness, not our own.
God also kept his promise to Abraham. Many nations came from him and the two major world religions — Christianity and Islam — claim Abraham as their father. His name truly is great, but Jesus is greater.