Paul is admitting here that even the lack of self-awareness of any negligence on his part doesn’t prove his faithfulness and obedience to God…for only God can judge.  As Believers we are all held accountable to…responsible for…and entrusted with the Gospel Message.  To paraphrase II Corinthians 10:18,  We can’t just hear the Word to be in right standing with God…we must obey it.  And in the end, we will all stand before the Judgment Seat of our Lord.