Singers were appointed to worship and praise the LORD, and as they did so, God fought for Judah and defeated their enemies. This teaches us that in the time of temptations, trials, etc., we can have the victory by praising and worshipping the Lord Jesus Christ. Paul and Silas had been cast into prison for preaching the gospel of Jesus Christ. Instead of moaning and groaning, they got their minds off themselves, and begin to sing praises unto their God. Because of this move of the Holy Spirit, Paul baptized the jailor and his household.
Praise decentralizes self.
We get our mind off of our own selves and our problems when we minister to the Lord in true worship.