In Rom 10:5, Paul describes the righteousness of the law by saying, “The man which doeth those things shall live by them.”   Doctrinally, “live by them” means staying alive by doing the words of the law [Deut 6:24].  Spiritually, though, we are to “live by them” as our way of life.  Jesus said, “Man shall not live by bread alone, but by every word that proceedeth out of the mouth of God,” [Matt 4:4].  In other words, these words are your life.  You are to live by them.

You live by them:  

To get saved and have eternal life.  Read Rom 10:9-10, 13.  You must trust what Jesus Christ has already done for you on Calvary to be saved.  Paul said, “Believe on the Lord Jesus Christ, and thou shalt be saved,” [Acts 16:31].  You get eternal life by believing what he said.

To live the eternal life you now have.  When you get saved, you are clueless how to live the life you have in Christ.  You are a new creature in Christ who must learn how to live your new life.  So, you go to these words to live the life that you have been given [Jn 10:10].  And when you do, your life is abundant.  Look, for example, at Lev 26:3-13.  Do you see all the blessings Israel was promised from God for simply living by the statues and commandments he gave them?  He was not manipulating them to behave.  He was telling them of the blessings they would receive from living by his words.  Most Christians today don’t live by God’s words.  These words are not their life.  And that is a tragic mistake.

To keep from experiencing adverse consequences.  When you get out of line with these words or disobey these words, there are consequences.  God sees everything you’re doing.  You cannot hide your disobedience from him.  Look what happens when you despise his words, Prov 13:13.  In Lev 26:14-46, you can see for yourself that the consequences of Israel’s disobedience were horrendous.  God will discipline and chasten you to bring you back into the blessing of his words.  According to Heb 12:10-11, God wants us to be partakers of his holiness.  He wants us to yield his peaceable fruit of righteousness.  

Conclusion: Live by these words.  If you aren’t saved this morning, then believe the Lord Jesus Christ so that you can live forever.  If you are already saved, then start living by God’s words.  Make sure everything in your life is in accordance with what God says.  That’s how you are supposed to live.  You live by them.