'Unable' in the Bible

When the king of Moab realized that the battle was going strongly against him, he took 700 expert swordsmen to attempt to break through to the king of Edom, but was unable to do so.

They served some for the men to eat, but when they ate the stew they cried out, “There’s death in the pot, man of God!” And they were unable to eat it.

Then Rezin the king of Syria, and Pekah son of Remaliah, the king of Israel, came up to Jerusalem to battle; and they besieged Ahaz, but were unable to conquer him.

"Don't let Hezekiah deceive you, because he will prove to be unable to deliver you from my control. And don't let Hezekiah make you trust in the LORD by telling you, "The LORD will certainly deliver us and this city will not be handed over to the king of Assyria."