“And at midnight Paul and Silas prayed, and sang praises unto God: and the prisoners heard them. And suddenly there was a great earthquake, so that the foundations of the prison were shaken: and immediately all the doors were opened, and every one’s bands were loosed.” – Acts 16:25-26
The devil seeks to be worshiped, he is prideful, selfish, and jealous. So two of the things he hates most and will flee from quickest is jeering or belittling toward him, and praise toward God. Besides the simple aspect of it really annoying the pants off of Satan (which is always a fun and desired benefit) there is great power in praise as a weapon of spiritual warfare for two major reasons.
The first being that it brings confusion to the enemies camp, and the second being that it brings God into yours. Time and time again through scripture we see accounts of the Israelites setting singers and musicians as their front line in battle, where the most effective weapon in the arsenal belongs. As they do this and the praises of the people begin to go up, the glory of God comes down upon the worshippers and confusion comes down upon the enemy as they scatter, flee, and even turn on themselves and each other.
“And when he had consulted with the people, he appointed singers unto the Lord, and that should praise the beauty of holiness, as they went out before the army, and to say, Praise the Lord; for his mercy endureth for ever. And when they began to sing and to praise, the Lord set ambushments against the children of Ammon, Moab, and mount Seir, which were come against Judah; and they were smitten (by each other).” – 2 Chronicles 20:21-22
As if confusing the enemy and causing them to flee and run amuck isn’t enough, praise assures the power of God will enter your situation by assuring that He Himself enters your praise. You see, true praise (not entertainment, showboating, or the seeking of vain self glory and praise which will cause God to depart and evil spirits to enter as they fluff you up and mock God. Remember the devil wants to be praised so he loves when people seek self praise because glorifying self glorifies him while robbing God), but when true praise is offered directly to God from you it creates an atmosphere that God Himself is willing to inhabit.
“But thou art holy, O thou that inhabitest the praises of Israel.” – Psalms 22:3
So knowing the strength and might of our God, the creator of all things, there is really never any reason to be worried as long as we are in right standing with God. Instead we should purpose in every situation to come to the Lord in prayer, praise, and supplication and wait patiently on Him as He inters our situation through the atmosphere of praise and changes everything. When true and pure praise goes up God shows up, demons flee, angels bow, and victory is won in the power of the presence of true praise.
“Why art thou cast down, O my soul? and why art thou disquieted in me? hope thou in God: for I shall yet praise him for the help of his countenance (face/presence/appearing).” – Psalms 42:5