James 5:16b The prayer of a righteous person is powerful and effective.

Literally: The prayer of a righteous person is great power working. Amplified Version says: The prayer of a godly person is powerful. It makes things happen. We see the prayers of a righteous person makes things happen. In Cor.5:21, we know through trusting Jesus our sins are forgiven and HE declares us righteous. Therefore, by trusting Jesus, we have access to the Throne of God, and our prayers are powerful and effective. Our prayers are powerful because we call upon the all-powerful God, the creator of the universe and nothing is impossible to HIM. God tells us why we should trust HIM, pray to HIM, and expect HIM to answer.