2 Kings 10:7 (KJV)

And he that was over the house, and he that was over the city, the elders also, and the bringers up of the children, sent to Jehu, saying, We are thy servants, and will do all that thou shalt bid us; we will not make any king: do thou that which is good in thine eyes.

Then he wrote a letter the second time to them, saying, If ye be mine, and if ye will hearken unto my voice, take ye the heads of the men your master’s sons, and come to me to Jezreel by to morrow this time. Now the king’s sons, being seventy persons, were with the great men of the city, which brought them up.

And it came to pass, when the letter came to them, that they took the king’s sons, and slew seventy persons, and put their heads in baskets, and sent him them to Jezreel.

And there came a messenger, and told him, saying, They have brought the heads of the king’s sons. And he said, Lay ye them in two heaps at the entering in of the gate until the morning.

And it came to pass in the morning, that he went out, and stood, and said to all the people, Ye be righteous: behold, I conspired against my master, and slew him: but who slew all these?