But who can detect all of his errors?

To suffer and be despised. - St. John of the Cross

Even when we deserve it - when our lies are all found out.  Not only as the result of an examination of conscience, but even when our neighbor may convict us of some hidden sin.  Perhaps an 'enemy' will call us out. Only when we are 'down and they're counting - When your secrets all found out...'  . might we come to recognize our hidden faults.  The upside of all of this is the favor those who accuse and despise us do for our souls.  I often remind myself, even though it hurts at times:  If a good man reproves me, it is kindness.  As well as: Faithful are the wounds of a friend; profuse are the kisses of an enemy. - Proverbs 27:6

From my hidden faults acquit me O Lord.

The Psalms tell the story - which is why they are so helpful for us to pray - not just recite.  It is also why self-knowledge is so important for us at every stage of our life - it is a necessary part of our 'purgation' or purification.

Sin speaks to the sinner
in the depths of his heart

There is no fear of God
before his eyes.

He so flatters himself in his mind
that he knows not his guilt. - Ps. 36

"Sin speaks to the sinner in the depths of his heart ... he so flatters himself in his mind that he knows not his guilt."  Like I said, we have an immense capacity for self delusion.  Which is why it is so advantageous for us to allow ourselves to be taught, to be corrected, even to be despised.

It is the Holy Spirit who convinces us and the world concerning sin, righteousness and judgement.

It's important to remember that the Lord accompanies us in and through these meditations in the deepest recesses of the cell of self-knowledge, as St. Catherine might say.  He was there when we knew not our sins and he is there when we uncover them, as it were.  We need to understand this so as not to get discouraged, even though we can say:

My sins so overcome me,
so that I can no longer see.
They are more numerous than the hairs of my head; 

my courage fails me. - Ps. 40

We need to trust in the Divine Mercy, as we struggle to  'lay aside every encumbrance of sin which clings to us'.  Confidence and love.

O Eternal Word, Word of my God, I want to spend my life in listening to You, to become wholly teachable that I may learn all from You. Then, through all nights, all voids, all helplessness, I want to gaze on You always and remain in Your great light. O my beloved Star, so fascinate me that I may not withdraw from Your radiance. - Prayer of Bl. Elizabeth of the Trinity

 

But who can detect all of his errors?
From hidden faults acquit me.

From presumption restrain your servant
and let it not rule me.
Then shall I be blameless,
clean from grave sin.

May the spoken words of my mouth,
the thoughts of my heart,
win favor in your sight, O Lord,
my rescuer, my rock! - Ps. 18