"Now the just shall live by faith; but if anyone draws back, My soul has no pleasure in him." Hebrews 10:38First of all, no one is just. But when a sinner becomes DEPENDENT on the Lord, there is faith. This faith is exactly what makes him just, pure and godly to come before Him.
But, if the just, pure and godly person stops being dependent on Him, then there will no longer be faith.
As a consequence, he will go back to being a lost sinner.