Genesis 17:9-10 And God said unto Abraham, Thou shalt keep my covenant therefore, thou, and thy seed after thee in their generations. This is my covenant, which ye shall keep, between me and you and thy seed after thee; every man child among you shall be circumcised.
When God appeared to Abram this sixth time, He changed his name to Abraham. He reaffirmed the covenant promise of Seed and Land (Christ and the Kingdom). Abraham’s response was to ”keep the covenant.” This is interesting, because God had made a one-way covenant with Abraham, meaning that for Abraham there was nothing to do. He did not walk through the cut animals, so he was not bound by oath to any terms of covenant. So what did God mean by ”keep?”
Keep here means believe: believe Me, believe My promise, trust My Word, and simply receive the covenant blessings of unconditional love I am giving you. And the Gospel of the New Covenant does the same thing for us: God the Father unconditionally grants all the blessings and promises earned for us by the death and resurrection of Jesus Christ. Nothing is left for us to do but believe and receive. Our faith is counted to us as righteousness.
Any good work we do or devotion we perform does not add to or complete the finished work of Christ. But actually we diminish faith by thinking we have to do something to earn grace. Then good works come naturally out of faith. Faith is primary: keep the covenant!