He who keeps the commandment keeps his soul, But he who is careless of conduct will die.This proverb gives us a different perspective of the same truth that Jesus taught in the Sermon on the Mount found in Matthew 7. Jesus told the crowd that many will say to Him in that day (Judgment Day) "Lord, Lord" but will not enter into the Kingdom of Heaven. That many will profess Jesus as Lord on the day of Judgment and yet will be told to depart due the Jesus' not knowing them. Jesus also clarifies who will enter into the Kingdom of Heaven. He says in verse 21, "...but he who does the will of My Father who is in heaven will enter." Now, we know that Jesus was the only man who ever truly did the will of the Father, perfectly and so it is fair to say that Jesus is not implying that no one but Him will be in Heaven. Rather, Jesus is teaching that those who have an attitude and lifestyle that is devoted to doing the things that please God, rather than self are the ones who will enter.
This proverb teaches the same thing only with a twist. It tells us that the one who keeps the commandment is the one who will keep his soul, sounding similar to the teaching that whoever seeks to save his life will lose it, but he who lose his life will save it. The man that puts what God wants over and above anything that self wants which is contrary to God will in fact keep his soul. This is saying exactly what Jesus is saying, when Jesus says, "He who does the will of My Father". Both verses are pointing to the same sort of man. The man who truly prays, "Thy Will be done".
The latter half of the proverb is where we see the twist though. I expected it to say something along the lines of, "but the man who forsakes the commandment will die" or "but he who rejects God will die". I thought it would say something particularly highlighting disobedience, but what do we see? The proverb writer heads to a deeper root to the problem. While disobedience to God will always be the result of the people Jesus spoke of when he labels them 'workers of iniquity' in verse 23 of Matthew 7, the proverb tells us 'why' they do so.
It says that 'he who is careless of conduct' will die. What does that mean? If someone is careless of conduct, there problem isn't usually that they outwardly, consciously disobey God. The real problem is that they do not even care about their conduct when it concerns God. They are careless, unconcerned and so self-centered that they do not care if there is even a God to be obedient to. This explains their puzzlement in that terrible Last Day of Judgment. They are standing there in front of Jesus Christ, the Great Judge crying out, "Lord! Lord! didnt' we serve you?" This is because they spent their lives professing to be attached to Christ and yet never truly concerned themselves with reading God's word to see what is required of them. They sat around telling one another, "Nobody's perfect", everytime someone tried to rebuke them for failing to meet God's standards instead of putting on the proverbial sackloth and ashes and heading to the cross of Christ for mercy. They were careless and in the end, it will cost them everything.