'Mustering' in the Bible

So the Spirit of the LORD took control of Gideon, who blew a trumpet, mustering the descendants of Abiezer to follow him into battle.

"Listen! There's a noise on the mountains like that of a great multitude! Listen! There's an uproar among the kingdoms, like that of nations massing together! The LORD of the Heavenly Armies is mustering an army for battle.

His sons will wage war, mustering a large army which will advance like an overflowing river and carrying the battle all the way to the enemy's fortress.