Q. When will the 144,000 who will be evangelizing the world be taken off the earth?
A. There is no need to assume that the 144,000 Jewish evangelists of the End Times will be taken off the earth prior to the end of the Millennium. Since they are sealed for protection, I see them as remaining and surviving on earth throughout the seven years of Tribulation.
I suspect that after the time of worldwide evangelism, which will take place in the first half of the Tribulation, they will migrate to the city of Petra for the second half of the Tribulation. They will be among the Jews who welcome the return of Yeshua at Petra, then enter the Messianic
Kingdom with Messiah and have a special role in the Kingdom as spelled out in Revelation 14:1-5. After the Kingdom, with all believers, they will enter into the eternal order.