'Able' in the Bible

Now when all the Moabites heard that the kings had come up to fight against them, they gathered themselves together, all who were able to put on armor, and upward, and stood on the border.

Now therefore, please give pledges to my master the king of Assyria, and I will give you two thousand horses, if you are able on your part to set riders on them.

Thus says the king, 'Don't let Hezekiah deceive you; for he will not be able to deliver you out of his hand.