The Bible says that 144K people of Revelation are the sealed Jews (Rev. 7:4) who will be redeemed from the earth. People interpret this passage differently. If I say it more detailed way than what I wrote you before:
(1)Some scholars interpret that the 144K chosen Israelites are clearly the selected people as God's children from 12 tribes. Some specific group of scholars think that only this 144K Israelites will be saved as the Bible says and that this passage doesn't day anything about the salvation of gentile church people.
(2)Some Replacement Theologians figuratively interpret the Bible. They insist that Israelietes are replaced by gentile church who are spiritual Israelites. So, they argue that 144k people are not Israelites, but a symbolically large group of gentile church people. They think that God had forsaken Israelites because Israelites killed Jesus. The Crusade of Roman Catholic and the Holocaust of Nazi came from this ideology.
(3)Some Dispensational Theologians believe that 144K are Jews. They think that real church is constituted by both Jewish church and gentile church. Therefore, both the symbolically many pure Israelites together with other believing gentile Christians will be saved at the end time. The movement of Israel Recovery belongs to this ideology.
(4)The Jehovah’s Witnesses wrongly claim that a group of their founders and pioneers constitute the group of 144K. They believe that all the churches are replaced by the followers of their doctrine. Most heresies think that only their people are saved. The number is 144K.
I follow the third view that is based on the more literal interpretation rather than figurative interpretation or the theological doctrines.