Genesis 6:9 These are the generations of Noah: Noah was a just man and perfect in his generations, and Noah walked with God.
Noah responded to God’s promise by walking with God. Noah believed God’s Word, listened to Him, found grace; he followed up that faith with obedience. Trust and obey. He built the ark over a long period of time, an apparently foolish thing to do in the desert while enduring the mockery of a perverse generation. But he did it just because God told him to.
Noah believed God and His Grace, and like Abraham, it was counted to him as righteousness. Grace and faith made him a just man and perfect in his generations. In faith and obedience he walked with God. He walked with God because he found grace; he did not walk with God in order to find grace and earn His favor. And so it happened, that Noah’s faith in grace saved him and his family, and the air-breathing animals.
And so it is with us: we respond to grace by walking with God. We trust and obey. After we are “saved by grace through faith,” then we do good works. Ephesians 2:10: ”For we are his workmanship, created in Christ Jesus for good works, which God prepared beforehand, that we should walk in them.” Like Noah, that is our response. ”We love him because he first loved us.”
The end result of grace: we are saved! 1 Peter 3:20-21: ”In [the ark] a few, that is, eight persons, were brought safely through water. Baptism, which corresponds to this, now saves you…through the resurrection of Jesus Christ.” We are saved by grace; therefore we walk with God.