'Understand' in the Bible

Yahweh looked down from heaven on the children of men, to see if there were any who did understand, who did seek after God.

When I tried to understand this, it was too painful for me;

They don't know, neither do they understand. They walk back and forth in darkness. All the foundations of the earth are shaken.

A senseless man doesn't know, neither does a fool understand this:

Our fathers didn't understand your wonders in Egypt. They didn't remember the multitude of your loving kindnesses, but were rebellious at the sea, even at the Red Sea.

Let me understand the teaching of your precepts! Then I will meditate on your wondrous works.

I understand more than the aged, because I have kept your precepts.