Jesus said, "If a blind person leads a blind person, both of them will fall into a hole." (34 Thomas)

I do not always know what I know. This is why a teacher or mentor can be helpful.

I can sometimes be aware of what I do not know. This is when I may choose to learn more.

But too often I do not know what I don't know. I may even mistake a new problem - of which I know very little - as an old problem that I am confident of solving.

The physically blind seldom deny their condition. But the metaphorically blind are often certain of their keen sight.

Humility is a practical virtue. It is a paradoxical strength. Humility questions rather than proclaims, listens more and talks less. And in doing so is more likely to perceive the hole.

Synoptic parallels are Luke 6:39 and Matthew 15:11-14.