'Heavy' in the Bible

But Moses' hands were heavy; and they took a stone, and put it under him, and he sat on it. Aaron and Hur held up his hands, the one on the one side, and the other on the other side. His hands were steady until sunset.

You will surely wear away, both you, and this people that is with you; for the thing is too heavy for you. You are not able to perform it yourself alone.