2 Kings 3:21

Now all the Moabites heard that the [three] kings had come up to fight against them, and all who were able to put on armor, as well as those who were older, were summoned and stood [together in battle formation] at the border.

1 Kings 20:11

The king of Israel answered, “Tell him, ‘A man who puts on [his armor to go to battle] should not boast like the man who takes it off [after the battle has been won].’”

Ephesians 6:14

So stand firm and hold your ground, having tightened the wide band of truth (personal integrity, moral courage) around your waist and having put on the breastplate of righteousness (an upright heart),

Treasury of Scripture Knowledge

Summary

And when all the Moabites heard that the kings were come up to fight against them, they gathered all that were able to put on armour, and upward, and stood in the border.

Bible References

Put on armour

1 Kings 20:11
The king of Israel answered, “Tell him, ‘A man who puts on [his armor to go to battle] should not boast like the man who takes it off [after the battle has been won].’”
Ephesians 6:14
So stand firm and hold your ground, having tightened the wide band of truth (personal integrity, moral courage) around your waist and having put on the breastplate of righteousness (an upright heart),