A Praise Banner Guard is a part of the worship team that goes out before the army with the ark of the Lord.

2 Chronicles 20:17-22
17 Ye shall not need to fight in this battle: set yourselves, stand ye still, and see the salvation of the LORD with you, O Judah and Jerusalem: fear not, nor be dismayed; tomorrow go out against them: for the LORD will be with you.
18 And Jehoshaphat bowed his head with his face to the ground: and all Judah and the inhabitants of Jerusalem fell before the LORD, worshipping the LORD.
19 And the Levites, of the children of the Kohathites, and of the children of the Korhites, stood up to praise the LORD God of Israel with a loud voice on high.
20 And they rose early in the morning, and went forth into the wilderness of Tekoa: and as they went forth, Jehoshaphat stood and said, Hear me, O Judah, and ye inhabitants of Jerusalem; Believe in the LORD your God, so shall ye be established; believe his prophets, so shall ye prosper.
21 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 forever.
22 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.

We help to welcome in the presence of the Lord and inspire others to open up and begin to praise and worship God. The rewards personally, are almost indescribable; there is an intimacy in worship that may not have been possible without the banners.

2 Samuel 22:33-37 KJV
33 God is my strength and power: And he maketh my way perfect.
34 He maketh my feet like hinds' feet: and setteth me upon my high places.
35 He teacheth my hands to war; so that a bow of steel is broken by mine arms.
36 Thou hast also given me the shield of thy salvation: and thy gentleness hath made me great.
37 Thou hast enlarged my steps under me; so that my feet did not slip.