11:7And when they have finished their testimony, the beast that comes up out of the abyss will make war with them, and overcome them and kill them.

And when they had finished their testimony,

This is 3 and 1/2 years (verse 3); some feel this is half way through the tribulation. They are immortal until their work is done. All of our life spans are fixed by God (Job 7:1-10, Hebrews 9:27-28, and James 4:13-17)

the BEAST that comes out of the ABYSS

This is the first mention of the BEAST. John does it so matter of fact that we wonder if he hadn't seen 'the BEAST' before but just didn't write it down. On the other hand, the two witnesses are not in chronological order so this may be at the beginning of John's vision and just now he is getting around to writing it down. He refers to the BEAST later in Revelation 13:1,7 and Revelation 17:8.

The ABYSS, the evil abode, is so bad that even the evil spirits do not wish to be there, Revelation 9:1-2,11.

So scholars believe this 'coming up from the ABYSS' is a mimic of the resurrection of Christ. How else will the world accept this evil-occupied human as "Messiah" (he is the only one to be able to kill the two witnesses. Whether the BEAST is in suspended death/trance and then "wakes up" is not clear. Mystic Eastern cults claim such suspension.

  1. will make war with them,

    Weaponry will be used to kill them. This follows Daniel's prophesy in Daniel 7:17-21-22.

  2. and overcome them and KILL them.

    With the two witnesses' death , it appears that the last great obstacle to total evil control of the earth has been conquered. The 144,000 witnesses in chapter 7 seem to remain until the dragon makes war with the 'rest of the woman's offspring' (Revelation 12:17).