God commands us to live holy and obedient lives; lives of righteousness and righteous acts. However, our righteous acts are filthy rags if we continue to live in sin. Unfortunately, many misuse the first half of Isaiah 64:6 in order to justify living in sin. They say God doesn’t care if we live righteously because he says our righteous acts are filthy rags and therefore there is no reason to stop sinning. But, let’s add a little bit of context to this one verse by reading verses 5 through 7.
Isaiah 64:5 You come to the help of those who gladly do right, who remember your ways. But when we continued to sin against them, you were angry. How then can we be saved? 6 All of us have become like one who is unclean, and all our righteous acts are like filthy rags; we all shrivel up like a leaf, and like the wind our sins sweep us away. 7 No one calls on your name or strives to lay hold of you; for you have hidden your face from us and made us waste away because of our sins.
The righteous acts are considered filthy rags because they are accompanied by sinful acts. They continued to sin. Continuing to live in sin is what made them unclean and made their righteous acts like filthy rags. Then look what happened; their sins swept them away, God hid His face from them, and they wasted away because of their sins.
Here is an analogy of how righteous acts can be like filthy rags when sin is still present: a man is aware that his wife is engaged in an adulterous relationship. He confronts her, yet she continues with the relationship. However, she serves her husband by having dinner on the table when he gets home from work, she washes & irons his clothes, and sincerely thanks him for working so hard. At the end of the day do you think her husband cares for, or appreciates, the “righteous acts” or good things she does for him? No! Her continued sin and lack of repentance makes all the righteous acts seem like filth because of her adultery (sin).
So, don’t stop the righteous acts. God calls us to holiness and obedience. Rather, stop living in sin because continuing to sin is what makes you unclean. And remember, it is not of your own might that you can live in righteousness; it is only in Christ and by his grace that you can put the flesh to death, flee sin, and become a slave to righteousness.