6 Then Jehu wrote them a second letter, saying, “If you are on my side and will obey me, take the heads of your master’s sons and come to me in Jezreel by this time tomorrow.” Now the royal princes, seventy of them, were with the leading men of the city, who were rearing them.

Read 2 Kings 10:6 Using Other Translations

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.
Then he wrote to them a second letter, saying, "If you are on my side, and if you are ready to obey me, take the heads of your master's sons and come to me at Jezreel tomorrow at this time." Now the king's sons, seventy persons, were with the great men of the city, who were bringing them up.
Jehu responded with a second letter: “If you are on my side and are going to obey me, bring the heads of your master’s sons to me at Jezreel by this time tomorrow.” Now the seventy sons of the king were being cared for by the leaders of Samaria, where they had been raised since childhood.