The purpose of the law is to reveal our sinfulness and bring us to Christ. When Christ refers to the commandments, He is using it to expose sin. Pastor David Moore writes:
And as he was setting out on his journey, a man ran up and knelt before him and asked him, “Good Teacher, what must I do to inherit eternal life?” And Jesus said to him, “Why do you call me good? No one is good except God alone. You know the commandments: ‘Do not murder, Do not commit adultery, Do not steal, Do not bear false witness, Do not defraud, Honor your father and mother.’” And he said to him, “Teacher, all these I have kept from my youth.” And Jesus, looking at him, loved him, and said to him, “You lack one thing: go, sell all that you have and give to the poor, and you will have treasure in heaven; and come, follow me.” Disheartened by the saying, he went away sorrowful, for he had great possessions. And Jesus looked around and said to his disciples, “How difficult it will be for those who have wealth to enter the kingdom of God!” (Mark 10:17-23 ESV)
It is interesting how the Lord went about finding this man out. Notice that Jesus only presented him with the parts of the Ten Commandments that deal with man-to-man relationships. The first four commandments which deal with man to God, He leaves unmentioned. There is no question that the young man has violated these , but the Lord wants to expose the self righteousness of this earnest enquirer, and he wants him to see that whilst he seeks eternal life, in his own mind he actually doesn’t have a need for it.
When the young man says of these laws “Master, all these I have observed from my youth.” I believe him. The chances are good that he had never committed adultery, that he had not murdered anyone, that he was generally honest, truthful, and honoring of his parents – at least on a superficial level. But if he is suggesting, as he is, that he had never murdered – even with his tongue, that he had not committed adultery – even in his heart, that he had never spoken anything less than the whole truth, then we can only marvel at his blindness and inability to see the truth about himself.
Let me tell you something, the truth about ourselves is hard. We can give man a softer image, we can proclaim him as generally good, mostly kind and humanitarian – but the truth is we are wicked to the bone, we are selfish, depraved, we are ungodly, we are by nature the enemies of God we are everything we would rather not be and that is the hard truth, and you cannot proclaim a true gospel without facing men with the hard truth about ourselves. I don’t see too much “seeker sensitivity” here. I see hard realities. Tough, damning statements, that tell the truth about who men are and what they are like. (“The Hard Gospel”)