The words of the Lord, which say that the unrighteous should continue to do unrighteousness and the unclean still be defiled, do not mean that He approves unrighteousness, wrongs, and defilements. They point only to the free will given by God to man, which He in no way constrains.
The divine laws are needed not by God, but by men. By conforming themselves to them, men can attain likeness to God, which is the true good for every human being.
God desires the righteous to advance and rise higher in righteousness. At the same time, He is long-suffering toward sinners, awaiting their repentance and conversion to Him. He does this in view of the remembrance of His near coming and of recompense to each according to his works.