Genesis 6:18, 22 But with thee I will establish my covenant; and thou shalt come into the ark, thou, and thy sons, and thy wife, and thy sons’ wives with thee….Thus did Noah; according to all that God commanded him, so did he.
God promised to establish His covenant with Noah, while all the rest of mankind would suffer and die in the Great Flood Judgment. Noah believed God; he believed God’s Grace, and he also believed His Judgment: enough to build an ark in the desert, how to build it, when to build it, where to build it, whatever it took.
Noah responded to God’s Word and to God’s Grace. He believed and obeyed. “He did all that God commanded him.” Noah did so because the Lord made a covenant with him. We also obey and do what God commands (live a good life) because God established His covenant with us in Baptism, renews His covenant in Communion, and reminds, confirms, comforts, and reassures us in it every time we hear the Gospel. We believe it, receive it, and live according to it.
We respond to Grace and Salvation by actually doing His will, as expressed in His Commands. We fail, but we keep coming back in repentance and faith in the gospel. And we pray for the Father to make us better people in the Lord’s Prayer. We find grace; we enter into the ark, which symbolizes Jesus and His Salvation; we live by faith; we are saved; then we do what He says.