When the Jews finished rebuilding the wall of Jerusalem, Nehemiah knew that they needed to celebrate this great event. Therefore, he had the people go up on the wall,
“So I brought the leaders of Judah up on the wall, and appointed two large thanksgiving choirs. One went to the right hand on the wall toward the Refuse Gate. After them went Hoshaiah and half of the leaders of Judah…” (Nehemiah 12:31-37).
Then in the other direction,
“The other thanksgiving choir went the opposite way, and I was behind them with half of the people on the wall…” (Nehemiah 12:38-39).
They split up, going opposite directions, only to meet on the other side, so that they formed one large group. This was a brilliant display of unity, and celebration for the city of Jerusalem. If you have unity with fellow-Christians, show your happiness, even as these Jews did.