Nehemiah 8:9-10 — And Nehemiah, which is the Tirshatha, and Ezra the priest the scribe, and the Levites that taught the people, said unto all the people, This day is holy unto the Lord your God; mourn not, nor weep. For all the people wept, when they heard the words of the law. Then he said unto them, Go your way, eat the fat, and drink the sweet, and send portions unto them for whom nothing is prepared: for this day is holy unto our Lord: neither be ye sorry; for the joy of the Lord is your strength.

This Christian life is full of paradoxes. Here’s another one. “Blessed are they that mourn”. …”Rejoice in The Lord always”. Well which one is it? Mourn, or rejoice?
The same paradox occurred to me this morning when we read the verses from Nehemiah, above. The people requested that the law be read to them. The governor (Nehemiah), priests and scribes complied, and made sure the people understood what they were hearing. The people, realizing how neglectful they had been were properly moved to mourn.
Are you the same? I am, and I hope that you are. When I realize that I have wondered off the right path, I am moved to mourn.
But Nehemiah told the people not to mourn, but rather to rejoice, and to be strengthened by their joy. How are we to do that? It comes from the realization that our God — who is the only God — is a gracious God, and when our sins are forgiven, they are forgotten. “As far as the east is from the west, so far hath he removed our transgressions from us.” (Psalm 103:12) Yes, indeed, we should mourn, and know the blackness of our sin — but when we set that against the knowledge that we are justified and are being made holy, and that insofar as we are faithful to confess our sins, He is faithful to forgive them, how great our joy should be.
Joy is more than just a natural result of knowing that we are redeemed and being sanctified. Maclaran points out that it is a duty. “Rejoice in The Lord” is not a suggestion. There is a popular misconception that we are at the mercy of our emotions. In truth, of course, we do have some control and can develop more. And we must “Rejoice evermore” (1 Thessalonians 5:16) — even when circumstances, however dire, might suggest otherwise!
So then, even when we are repentant, even when times are hard, we are to rejoice — and when we rejoice, therein lies our strength. The merry heart, the proverb says, is good medicine. When we are filled with the joy of The Lord we have a barrier against attacks of sin, the world, and the Devil! When we allow ourselves to be undermined by depression, morbidly linger over our sins or fail to recognize the hand of God in even the direst of circumstances, we are at risk — so mourn not, nor weep!