'Able' in the Bible

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.

Now therefore, I pray thee, give pledges to my lord the king of Assyria, and I will deliver thee two thousand horses, if thou be able on thy part to set riders upon them.

Thus saith the king, Let not Hezekiah deceive you: for he shall not be able to deliver you out of his hand: