Question: "Why did Jesus tell the rich young ruler he could be saved by obeying the commandments?"
Answer: To understand Jesus’ response to the rich young ruler’s question—“What must I do to be saved?”—we must consider three things—the nature of the rich young ruler, the purpose of his question, and the essence of the gospel of Jesus Christ. At first glance, it appears that Jesus is saying that the young man, and by extension all people, must obey the commandments in order to be saved. But is that really what He was saying? Since the essence of the salvation message is that we are saved by grace through faith (Ephesians 2:8–9), why would Jesus offer the rich young ruler an “alternative plan”?
The story of the rich young ruler is found in all three of the Synoptic Gospels, Matthew 19:16–23, Mark 10:17–22, and Luke 18:18–23. The man is described as a “ruler,” which means a prince or magistrate of some sort. Since no Roman ruler would address Jesus as “teacher” or “master,” it is assumed that this man was a ruler in the local synagogue. This man had “great wealth” (Luke 18:23), and the impact of wealth is the lesson Jesus was teaching to His disciples. He was using this man as an example of the corrupting power of riches and its detrimental effect on the desire for eternal life. The fact that the man was young (Matthew 19:20) and already wealthy would seem to indicate that he had enjoyed a life of riches and ease and had become accustomed to it. When he comes to Jesus asking about eternal life, Jesus uses the opportunity to teach about money, not about salvation by works.
The first thing Jesus says to the man’s greeting, “Good teacher,” is to remind him that no one is good except God. Jesus was not denying His own divinity. Rather, He saw beneath the flattery to the man’s heart which was self-seeking and self-promoting. He was attempting to curry favor with Jesus by falling on his knees before Him (Mark 10:17), complimenting Him, and ascribing to Him a divine attribute he never really believed Jesus possessed. Perhaps realizing his hypocrisy was perceived by Jesus, the man ignored His question, “Why do you call me good? Only God is good.” Jesus, knowing the man’s heart and his self-righteousness, recited some of the Ten Commandments and told the man to obey them. This was not a refutation of His earlier teachings on salvation by faith. Jesus said this, no doubt, to try him and to convince him that he had by no means kept the commandments, and that, in supposing he had, he was deceiving himself. At this point, Jesus said the one thing that, knowing the man’s heart, would convince him that he was, after all, a wretched sinner in desperate need of salvation. Jesus points out the young man’s weak spot, his wealth.
The man’s heart condition was made poignantly clear by Jesus’ command that the man sell all and follow Him. His face fell, and he went away sad because he could never part with his great wealth, not even in exchange for eternal life. By claiming he had kept the Law, the man was declaring that he had obeyed the first commandment to love the Lord supremely and above all things, including wealth. He was also saying he loved his neighbor more than himself. But if he loved God and fellow-creatures more than he did his property, he would be willing to give up his wealth to the service of God and of man. But that was not the case. He had made an idol of his wealth and loved it more than God. He had not kept the commandments from his youth, nor had he kept them at all. He rejected even this last opportunity to do good with his treasures and seek his salvation by obeying God, choosing instead to turn away from the Savior and not renew his inquiry about eternal life. He probably never returned.
By His words to the rich young ruler, Christ did not mean to say that any man would be saved by the works of the Law, for the Bible teaches plainly that such will not be the case (Romans 3:20, 28; 4:6; Galatians 2:16; Ephesians 2:9; 2 Timothy 1:9). Rather, He was using the man’s wealth which had corrupted his heart, as an example to the disciples and us.