I agree with OldThenNew when he says not to cause strife. I'd only like to show the exchange between the rich man and Christ in its entirety and then share my counter-conclusion.
Matthew 19:16
So the rich man posed a question asking Christ what he must
do to receive eternal life.
Matthew 19:17
I didn't add to this passage and I didn't take away from it. Christ said in order to enter into life keep the commandments.
Let's read Mark's version...
Mark 10: 17
Here again, the man asked what should he
do to inherit eternal life.
Mark 10:18-19
Again, I didn't add to this passage and I didn't take away from it. To answer the man's question Christ points the man to keeping the commandments. Let's take Luke's version...
Luke 18:18-20
In each of these passages, Christ immediately answers the man's question by pointing him towards following God's commandments in order to inherit eternal life. It's only *after* the man says he's been *successfully* keeping them that an additional issue is brought up. He "
lacked one thing" apart from what he was
*already successfully doing* to inherent eternal life. He lacked the faith of/in Christ, which would've been particularly proven by him if he sold all he had and followed Christ (since Christ knew what this man truly had faith in for his personal salvation/security/protection/freedom, etc...his wealth).
Also I want to point out that Christ never says to this man anything about believing Christ will die for him on the cross, even though it was the perfect time to say it...but Christ never tells him one thing about the cross as an answer to his "eternal life" question. The Cross was Christ's secret mission (explained by Paul) that makes the Kingdom of God possible; that makes the answer Christ did give to the man possible ("
his work on the cross snatched the power of sin and death from satan setting us free from the *penalty* of the law, restoring our good standing with God so we can finally walk in His ways in love").
So one can't lead off by saying
keeping the law *only* is not good enough to inherit eternal life (which is a true statement) but then conclude that
belief in the cross *only* is good enough. It's the same error, because belief in the cross *only* would mean the person then
lacks keeping the commandments else we make Christ's words to this rich man a lie. Again Christ said the man lacked
just one more thing, which meant what that man was
already doing was/is still required (proven by Christ's first answer).
Revelation 12:17So the dragon was enraged with the woman, and went off to make war with the rest of her children, who (1) keep the commandments of God and (2) hold to the testimony of Jesus.
Revelation 14:12Here is the patience of the saints: here are they that (1) keep the commandments of God, and (2) the faith of Jesus.
For many Christians today the scenario is flipped. If they could ask Christ face to face what they must
do to inherit eternal life - telling Christ they have had faith in him & his work on the cross since their youth - Christ would again say, "well you lack one thing" but once again point straight towards keeping God's commandments...because Christ is the same yesterday, today...and forever.