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.”
So the Levites stilled all the people, saying, “Hold your peace, for the day is holy; neither be ye grieved.” And all the people went their way to eat, and to drink, and to send portions, and to make great mirth, because they had understood the words that were declared unto them.
Nehemiah 8:9-12

There is a time for rejoicing, and Nehemiah, Ezra, and all the others were rejoicing because of the finished wall, the reading of the law of Moses, and the explanation of it, and the peoples mourning for their sins. After their repentance it is a time for rejoicing.

Rejoicing in the wonderful word of  God. Rejoicing in the LORD’S grace, mercy and love. Rejoicing in the forgiveness of their sins.

If you are a follower of Jesus Christ; you believe that Jesus died for your sins, that He was buried, and that He rose again, and you turned form your sin to Jesus, and confess that He is Lord, then you are a follower of Christ. If we do sin and confess our sins He is faithful to forgive us our sins (1 John 1:9).

If you are not a follower of Jesus Christ, then you are without hope, you are lost, you are a condemned sinner, you do not know God. You will never come to God in your own way or your own works. Turn to Jesus Christ today, before it is too late. Then there will be rejoicing in your heart and life, and there will be great rejoicing in heaven.