Nehemiah tells us the joy of the Lord is our strength… Why, exactly, is the joy of the Lord our strength?
This answer is because of the nature of joy; because of what joy is.
Joy is a remembering of certain secret realities. Joy is an expression of the hidden heart that declares God is truly good.
Matthew Henry reminds us the joy in this passage is indeed centered around feelings and thoughts for God. “Let it not be a carnal sensual joy, but holy and spiritual, the joy of the Lord, joy in the goodness of God, under the direction and government of the grace of God, joy arising from our interest in the love and favour of God and the tokens of his favour.”
A realization of God’s qualities inspires gladness in our heart stronger than any circumstance. He is Beauty, even if ugliness surrounds us. He is Kindness, though all men are hateful. He is splendid and shimmering beyond the stars. He is holy and perfect and pure beyond the most moral figure imaginable. He is light and cheer and good humor bursting far above our greatest moments of mirth. He is tender and compassionate enough to wring out rivers of happy tears.
And joy is the complete and indelible conviction that He is all of that forever, completely, despite any storm of emotion raging in us or any tempest of hatred raging outside of us.
In this sense joy is also a secret and heroic act of the will. It is the firm resolution to take heart in the very teeth of horror. Joy is intrinsically linked to hope. It is grounded in eternal truths that demand the flame of cheer is not snuffed because good things yet remain.
Joy in the Lord is our strength. It thrusts in the foreground of our mind again and again the truth that, though everything is taken from us, He can never be. And that is always reason to take heart and to keep our cheer to our very last breath.