“Sometimes scholars say that the Old Testament does not demand perfect obedience to the law. We must address this matter carefully because there is a sense in which the Old Testament requires perfect obedience and a sense in which it doesn’t. Let me explain. God saves his people, Israel, by grace. He enters into covenant with them and delivers them at the exodus. He does not demand that they obey the law perfectly to remain in covenant with him. But Yahweh threatens exile if his people become enslaved to evil. They will be judged by God if they harden their hearts, forsake the Lord and turn away from him. They will be blessed as his people if they keep the Torah. Such blessing is not conditioned on perfect obedience. Israel will show its faith in Yahweh by obeying him significantly and substantially, but not perfectly.” – Thomas Schreiner, The Nature of the Atonement: Four Views, p. 74 (emphasis mine)
I think the last part of what Schreiner says is significant for Christians to consider. In the same way that it applied to Israel, followers of Christ show their faith in Jesus by obeying him significantly and substantially, but not perfectly. Those two words, “significantly” and “substantially” are key. After all, this seems to be the thrust of a lot of what is said in the NT:
“Whoever believes in the Son has eternal life; whoever does not obey the Son shall not see life, but the wrath of God remains on him.” (John 3:36)
“And by this we know that we have come to know him, if we keep his commandments. Whoever says “I know him” but does not keep his commandments is a liar, and the truth is not in him, but whoever keeps his word, in him truly the love of God is perfected. By this we may know that we are in him…” (1 John 2:3-5)
“By this we know that we love the children of God, when we love God and obey his commandments. For this is the love of God, that we keep his commandments. And his commandments are not burdensome. For everyone who has been born of God overcomes the world. And this is the victory that has overcome the world–our faith.” (1 John 5:2-4)
These, of course, are just a few of the more common Scriptures that clarify what knowing and loving the Lord look like – obedience. So it seems adequate to apply Schreiner’s “significantly” and “substantially” to the life of Christians.