Satan is scared of it. Righteousness is the only thing that keeps you out of the devil reach. The bible says he that is begotten of God sinneth not and that wicked one toucheth him not. 1Jn 5:18
Secondly, the third foundation of faith after the word of God and love is righteousness. You cannot plead the promises while violating the principles. John 9:31, “Now we know that God heareth not sinners: but if any man be a worshipper of God, and doeth his will, him he heareth.”
If God does not hear sinners, it means the prayer of the sinner will not be answered. Sin destroys confidence without which faith is impossible. The bible says, “This is the confidence we have in Him that if we ask anything according to His will he heareth us.” If you have no confidence in Him you cannot have confidence in His word. Notice also that all the promises of provision and blessings are made to the righteous. Similarly, if you have no confidence in yourself because of sin, you cannot receive. Sin makes you feel disqualified.