Now when they have finished their testimony, the beast that comes up from the Abyss will attack them, and overpower and kill them. 8 Their bodies will lie in the public square of the great city—which is figuratively called Sodom and Egypt—where also their Lord was crucified. 9 For three and a half days some from every people, tribe, language and nation will gaze on their bodies and refuse them burial.10 The inhabitants of the earth will gloat over them and will celebrate by sending each other gifts,because these two prophets had tormented those who live on the earth. (Revelation 11:7-10 NIV)
After 1,260 days the two “witnesses” that God sends to Earth will fulfill their ministry (This is probably 30 days before Jesus returns: see Daniel 12:11). Then God will permit the “beast” who is the Antichrist, to attack them and kill them. This will result in the only celebration that is ever depicted as taking place during the tribulation. All the unbelievers (and there will be some from “every people, tribe, language and nation”) will gaze on the bodies (perhaps via television) and send each other gifts, as if it were Christmas time. In doing so they will be earning God’s final judgment, by showing such pleasure over the mistreatment of His loyal prophets.