David Spoke of secret faults in Psalms 19:12 Who can understand his errors? cleanse thou me from secret faults.
A good example of acheiving Holiness.
Thought secret faults and know faults are different and the resulting judgments are therefore different as well, the secret faults are not to be treated lightly.
Luke 12:47 And that servant, which knew his lord's will, and prepared not himself, neither did according to his will, shall be beaten with many stripes.
Luke 12:48 But he that knew not, and did commit things worthy of stripes, shall be beaten with few stripes. For unto whomsoever much is given, of him shall be much required: and to whom men have committed much, of him they will ask the more.
Therefore, teachers are not the same as commoners: James 3:1 My brethren, be not many masters, knowing that we shall receive the greater condemnation.