Are the 144,000 made up of members of a cult?
No. The 144,000 are Jews, not members of a cult. They are sealed from all the tribes of the children of Israel, as the text says. A cult claims its members will be the 144,000, but Scripture identifies them as Jews.
Les explains that as soon as the tribulation begins, God's two witnesses appear in Jerusalem and preach to the nation of Israel. Out of that preaching, the 144,000 Jews are sealed. He stresses that, contrary to a cult that claims its members will be the 144,000, these are Jews—all the tribes of the children of Israel are represented, not just two. Despite nearly 2,700 years of dispersion among the nations, they remain Jews, and God knows the tribe each one came from even if they do not.