2KI 10:6

6 Then he wrote a sefer [(letter)] the second time to them, saying, If ye be mine, and if ye will pay heed unto my voice, take ye the rashei anshei bnei adoneichem [(the heads of the male children of your master)], and come to me to Yizre'el by tomorrow this time. Now the Bnei HaMelech, being seventy persons, were with the Gedolim of the Ir, who were rearing them.