Paul often contrasted the righteousness that faith could obtain with righteousness based on the law.  Righteousness obtained by faith has been made available by Jesus dying on the cross for our sins.  This is why the Bible affirms that we are justified by faith, as well as by the blood of Christ.

Romans 5:1 (ESV)
¹ Therefore, since we have been justified by faith, we have peace with God through our Lord Jesus Christ.

Romans 5:9 (ESV)
⁹ Since, therefore, we have now been justified by his blood, much more shall we be saved by him from the wrath of God.

Thank God we can be justified by faith since we are all sinners and need the mercy and grace of God to be saved.  Justification by faith comes to all who obey the gospel of Christ, which is the power of God unto salvation (Romans 1:16).

Being justified by the law is much harder, if not altogether impossible, for us today.  It demands a life of sinless living.  Only one person has ever pulled that off, and that, of course, is Jesus, making it possible for Him to be our propitiation.

Romans 3:23-25 (ESV)
²³ For all have sinned and fall short of the glory of God, ²⁴ and are justified by his grace as a gift, through the redemption that is in Christ Jesus, ²⁵ whom God put forward as a propitiation by his blood, to be received by faith. This was to show God’s righteousness, because in his divine forbearance he had passed over former sins.

In contrast to this, Paul refers to the justification under the law described by Moses.

Romans 10:5 (ESV)
⁵For Moses writes about the righteousness that is based on the law, that the person who does the commandments shall live by them.

When Paul refers to a person doing the commandments, he is speaking of doing them perfectly.  That was what the law required because it could not set one free from sin (Acts 13:39).

Was God unjust for setting forth a law that demanded perfection?  The answer is no because the law was never meant to save a person.  The purpose of the law was to expose sin and discipline the sinner (Galatians 3:24), and it did exactly what it was meant to do.  This is why Paul was quick to defend the law, calling it holy, righteous, and good (Romans 7:12).

While we are not under the Law today, should we not strive to meet its standard?  We certainly have a better law today, a law that provides provisions for sin, primarily the cleansing power of the blood of Christ (1 John 1:7-9), but that does not give us a license to sin.  Remember, John once wrote, “…I am writing these things to you so that you may not sin” (1 John 2:1), and not sinning should be the goal of all of us.

Every new day should be a day wherein we strive not to sin.  Our aim should always be to live “by every word that comes from the mouth of God” (Matthew 4:4).  Still, it is very comforting to know that if we fail, “we have an advocate with the Father, Jesus Christ the righteous.”

As you wind down for the night, think about these things.