'Knows' in the Bible

He said, “While the child was still alive, I fasted and wept; for I said, ‘Who knows, the Lord may be gracious to me, that the child may live.’

Joab fell on his face to the ground, prostrated himself and blessed the king; then Joab said, “Today your servant knows that I have found favor in your sight, O my lord, the king, in that the king has performed the request of his servant.”

And even the one who is valiant, whose heart is like the heart of a lion, will completely lose heart; for all Israel knows that your father is a mighty man and those who are with him are valiant men.

For your servant knows that I have sinned; therefore behold, I have come today, the first of all the house of Joseph to go down to meet my lord the king.”