How come the tribe of Dan is not mentioned in Revelation chapter 7? What happened?
Most scholars believe that Dan was omitted because it was through the tribe of Dan that idolatry was introduced into the land after Solomon died (1 Kings 12:28-30). Jacob had prophesied in Genesis 49:17 that Dan will be a serpent by the roadside, a viper along the path, that bites the horse’s heels so that its rider tumbles backward. I believe he was hinting that Dan would be responsible for Israel’s fall back into idolatry.
There’s a tradition that Dan was a ringleader in the kidnapping and sale of Joseph into slavery, and another one that the anti-Christ will come from the tribe of Dan, but neither one of these can be confirmed Biblically. For these or other reasons, no one from the tribe of Dan is sealed. But God is merciful, and at the beginning of the Kingdom Age when the land is re-distributed, Dan will receive the first share. (Ezekiel 48:1)