like a mighty man - in the battle with the foe (Zec 10:3, Zec 10:5).
rejoice - at their victory over the foe.
children shall see it - who are not yet of age to serve. To teach patient waiting for God’s promises. If ye do not at present see the fulfillment, your children shall, and their joy shall be complete.
rejoice in the Lord - the Giver of such a glorious victory.