'Generation' in the Bible

The Lord said to Jehu, “Because you have done well in executing what is right in My eyes, and have done to the house of Ahab in accordance with everything that was in My heart, your sons (descendants) shall sit on Israel’s throne to the fourth generation.”

This is [the fulfillment of] the word of the Lord which He spoke to Jehu, saying, “Your sons (descendants) shall sit on the throne of Israel to the fourth generation.” And so it came to pass.