'Mercy' in the Bible

but {if they repent} in the land where they were taken captive and {repent} and beg you for mercy in the land of their captivity, saying, 'We have sinned and acted perversely and done wickedly,

Therefore he brought against them the king of the Chaldeans, and he killed their young men with the sword in the house of their sanctuary. He showed no mercy on a young man, a virgin, [the] elderly, or decrepit. He delivered all into his hand.