“For it is written, “Rejoice, you childless woman, who cannot give birth to any children! Break into song and shout, you who feel no pains of childbirth! For the children of the deserted woman are more numerous than the children of the woman who has a husband.””  
Galatians 4:27

In the word of God we’ve been shown examples of how expressions of faith in singing and shouting wrought astounding miracles, and the Bible says:
“For whatsoever things were written aforetime were written for our learning, that we through patience and comfort of the scriptures might have hope.”  Romans 15:4
They were written so we can learn from them and be inspired unto comfort, when you read about the walls of Jericho coming down because of the shout of the people of God, he says it’s written so you would be comforted in your situation, knowing that as you shout in faith, that challenge would become bread! Joy is such a tool:
“Therefore with joy shall ye draw water out of the wells of salvation.”  Isaiah 12:3
With Joy, you would fetch out the salvation you require- salvation from financial, emotional or physical mishap.
“Thus saith the LORD unto you, Be not afraid nor dismayed by reason of this great multitude; for the battle is not yours, but God’s. And when they began to sing and to praise… they were smitten.”  2 Chronicles 20:15,22
The battle was already won, even as they expressed their faith in God through singing. You’ve prayed, fasted, wept- now sing and shout for joy!