Job 9:20 KJV
If I justify myself, mine own mouth shall condemn me: if I say, I am perfect, it shall also prove me perverse.
Job 9:20, King James Version
In context
19 If I speak of strength, lo, he is strong: and if of judgment, who shall set me a time to plead?
20 If I justify myself, mine own mouth shall condemn me: if I say, I am perfect, it shall also prove me perverse.
21 Though I were perfect, yet would I not know my soul: I would despise my life.