'Strength' in the Bible

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

Then he said unto them, Go your way, eat the fat, and drink the sweet, and send portions unto him for whom nothing is prepared; for this day is holy unto our Lord: neither be ye grieved; for the joy of Jehovah is your strength.