Revelation 7 has the setting apart of 144,000 people from the tribes of both houses of Israel. After these people have been set apart John looks and there is a multitude that no one could number that came out of the tribulation. 144,000 are separate from the other people but there is some connection because the are listed so close together. There are over 1 million Jews believed to be in the messianic movement so this is something else. Then in Revelation 14 after the tribulation they continue to be set apart. They sing a new song before the throne and before the four living creatures and the elders. No one could learn the song except the 144,000 who had been redeemed from the earth. If The 144,000 do not make up the 2 witnesses that could come from the House of Israel and House of Judah. Then who are they and why are they set apart.