However, the Law is not of faith; on the contrary, "HE WHO PRACTICES THEM SHALL LIVE BY THEM."Galatians 3:12(NASB)
We are justified by grace through faith and not by works of the Law. The principles of the Law tell us what we should do and what we should not do, if we want to be perfect before God. However, the Law can never make us righteous before Him, but it places us under His condemnation - for the Law is not based on faith in God but on good works that are impossible for fallen man to achieve.
The Law is not based on gracious faith but on its own unattainable standard, which puts us under a yoke of condemnation. The standard it advocates is impossible for anyone to reach, for we are all sinners - and sinners need a Saviour.
God knew from the beginning that the Law, in all is guises and disguises is impossible for fallen humanity to achieve, and so God used the perfect Law as the instrument to contrast our own imperfections and inabilities with Christ's perfect standard - for the Law is a schoolmaster to point us to the one perfect Person Who fulfilled the Law on behalf of all who have faith in Him.
The only reason Christ could become the sin-substitute for mankind, was because He fulfilled every aspect of the Law perfectly. Christ identified with our utter sinfulness so that we could identify with His perfect sinlessness.
Christ lived a perfect life, fulfilling the demands of the Law on our behalf. He died on our behalf to pay the price for our sins and then rose again on our behalf so that He could give us His perfect life in the Person of the indwelling Holy Spirit. This He did so that we could be pronounced righteous before the Father and stand guiltless before the demands of the Law, for there is no condemnation to those that are in Christ Jesus.
Sadly, many Christians who are saved by grace through faith, fail to continue to live their lives by grace through faith and place themselves back under the unattainable, legalistic demands of the Law. Instead of rejoicing in Christ's finished work on their behalf, these born-again believers forget they have a new Christlike-life within and work at achieving an unattainable righteousness through their old sin nature. Sadly, they keep trying to achieve the righteousness that was purchased for them once and for all at the Cross, never fully understanding that they are already clothed in the righteousness of Christ: "For whoever believes in Him is not condemned."
Let us keep that old self nailed to the Cross and let Christ live His life through us, as we rest in Him - by grace through faith.
Heavenly Father, I know that I am unable to achieve the righteous standard that You require of me. I see that Christ is the only one Who has ever lived according to Your perfect and holy requirements. Thank You that by grace through faith, You have imputed me with His righteousness and graciously given me all I need to live as You require of me. Help me to live in Christ, Who has become for me wisdom, righteousness, holiness, and redemption. In Jesus' name I pray, AMEN.