Nehemiah 8:10
Then he said to them, "Go your way, eat the fat and drink sweet wine and send portions to him for whom nothing is prepared; for this day is holy to our Lord; and do not be grieved, for the joy of the LORD is your strength."
The world tells you that your strength is through anxiety, fear, and tension. To be strong is, in the world's terms, to be frightened, distrustful, ready to strike back, and plagued by worry about what your enemy may do to you. Worldly "strength" is to cherish grudges and never forgive. But Scripture reveals an entirely different sort of strength and the root from which it springs. The joy of the Lord is the strength of the saints. Though they are watchful, they are not tense. Though they forgive, they are not suckers, saps, and losers. For they know that bitterness is like drinking poison and expecting the other guy to die. So they live in the life of the Blessed Trinity –that is, joy–and receive the power of that life to do what God wills. That is the greatest power there is.