“For He made Him who knew no sin to be sin for us, that we might become the righteousness of God in Him" (2 Corinthians 5:21).
I believe that justification by faith is the foundational truth of Christianity. You cannot know true rest and peace until you are convinced that you can never be made right in God’s eyes by your own works.
If you do not understand the perfect righteousness of Christ that is yours by faith, you will lead a life of toil and sweat, trying to please God through a legalistic, hopeless attempt to establish your own righteousness. But the truth is, you will never have any righteousness to bring to the Lord.
A familiar passage in Isaiah says that all our righteousness is as filthy rags in God’s sight (Isaiah 64:6). This does not mean that God despises our good works — not at all. God does want our righteous deeds and we should do all the good works that we can. But if you think they merit your salvation then they are no more than filthy rags.
Of course, you may feel good because of the good works you do. For instance, you will probably enjoy a moment of victory and satisfaction whenever you resist temptation. But the next day you fall back into a sin and you quickly lose your joy. You think the Lord is angry with you and you think, “I’ll never make it.”
Such a roller-coaster ride of emotional highs and lows can result in a life of misery. Why? Because you are trying to please God in your flesh!
Beloved, no righteousness of the flesh will ever stand before God. Even the best people among us — the most moral, godly saints — have all failed miserably and fallen short of God’s glory. Not one of us can ever be accepted in the Father’s eyes by our own works. But the good news is that we are totally accepted by him through Christ.