This verse summarizes what Paul wrote in Romans 3:21-27. In addition, it serves as a useful, concise demonstration of the fact that salvation is not contingent on any good deeds or other behavior. It is a blessing that God has provided a way, but only one way, for humans to be declared "justified." The only way to do this is through faith, not through the works of the law. 
Paul reveals the glorious truth that man is justified by faith after we have confessed that we all have sinned and fallen short of God's glory. No one is good or righteous in God's sight. Without performing the law's deeds, we have been justified. We are justified by faith in Christ. Through the gift of redemption provided through Christ Jesus, we are free and unconditionally forgiven of our sins.
Justification through faith is only the first step in a lifelong journey of faith. Those who have been redeemed are called to live their daily lives according to their faith rather than by the works of the law. Our justification is just the beginning of a life in which we are called to live by faith. Hence, let us always remember to live our lives as Christians in this body by faith in the Son of God, who loves us and sacrificed Himself for all of us.

Dear Heavenly Father, Thank You for justifying me by faith without the deeds of the law. Thank You for accepting me through the Lord Jesus Christ. Thank You for enabling me to be clothed in Christ's righteousness through faith in Him and released from the shackles of the law through my faith in Him. Let me live by faith and not strive to gain Your approval by working out the law or doing works of the flesh. Knowing that Christ has set me free, may I live by faith in Him. 
In Jesus's name I pray. Amen.