'Strength' in the Bible

Judah said, "The strength of the bearers of burdens is fading, and there is much rubbish; so that we are not able to build the wall."

Then he said to them, "Go your way. Eat the fat, drink the sweet, and send portions to him for whom nothing is prepared; for this day is holy to our Lord. Don't be grieved; for the joy of Yahweh is your strength."