This technical phrase denotes the global populace of the time of the end who consistently oppose God (Rev. Rev. 9:20+), worship the beast (Rev. Rev. 13:8+), and reject the things of heaven in favor of the things of earth. They are the ones for whom the time of testing is purposefully designed (Rev. Rev. 3:10+).
εὐφραίνονται [euphrainontai] , the same root word describes eat, drink, and be merry [emphasis added] (Luke Luke 12:19). It is used Acts 2:26).1 Although they make merry for a few days, their triumph will be short-lived:
That the triumphing of the wicked is short, and the joy of the hypocrite is but for a moment? Though his haughtiness mounts up to the heavens, and his head reaches to the clouds, yet he will perish forever like his own refuse; those who have seen him will say, Where is he? He will fly away like a dream, and not be found; yes, he will be chased away like a vision of the night. The eye that saw him will see him no more, nor will his place behold him anymore. (Job Job 20:5-9)Although the time of the end is characterized by war and disruption, worldly enemies will unite in their hatred for these two witnesses and join hands rejoicing in their demise (Luke Luke 23:12).2
send gifts to one another
So great will be their elation over the death of these two prophets that they will declare a holiday and exchange gifts with one another in celebration (Ne. Ne. 8:10-12; Est. Est. 9:19-22). The elation of the earth dwellers over the death of the two witnesses provides evidence of the seriousness of the plagues which they meted out during their ministry. These two witnesses were not hated solely because they represented God, but all the more so because of their effectiveness at tormenting those who were affected by their plagues.
because these two prophets tormented those who dwell on the earth
Tormented is ἐβασάνισαν [ebasanisan] , which can describe torture in judicial examination, general harassment, or any kind of severe distress, especially physical distress. It is used to describe the results of paralysis (Mtt. Mat. 8:6), the torment inflicted by the demonic scorpions (Rev. Rev. 9:5+), the eventual torment feared by demons (Mtt. Mat. 8:29), the pain of childbirth (Rev. Rev. 12:2+), and the final torment of the unsaved dead (Rev. Rev. 14:10+; Rev. 20:10+). As prophets, they joined a long list of Gods servants who were hated by those to whom they were sent (1K. 1K. 18:17; 1K. 21:20; 1K. 22:8; Jer. Jer. 38:4; Mtt. Mat. 23:37; Luke Luke 13:33-34; John John 7:7, John 7:25; Acts Acts 5:33; Acts Acts 7:54-57; Acts Acts 17:5-7).
2 Demonstrating the political parable: My enemys enemy is my friend.