Revelation 11:5; Fire Out of Their Mouths

Revelation 11:5 And if any man will hurt them, fire proceedeth out of their mouth, and devoureth their enemies: and if any man will hurt them, he must in this manner be killed. 

The enmity of men against God’s witnesses must be very great at that time. God empowers His servants with special powers to defend themselves against the onslaught of the enemy.

For missionaries in the past and even today giving the gospel to hostile people groups, their protection has been their incessant prayers and the prayer support of their sending churches.

Our Lord Jesus commissioned these two witnesses as His messengers to a world in total rebellion, yet the mission is the same, with a heart of love to reach out to those who oppose themselves – Romans 10:12-17 For there is no difference between the Jew and the Greek: for the same Lord over all is rich unto all that call upon him. For whosoever shall call upon the name of the Lord shall be saved. How then shall they call on him in whom they have not believed? and how shall they believe in him of whom they have not heard? and how shall they hear without a preacher? And how shall they preach, except they be sent? as it is written, How beautiful are the feet of them that preach the gospel of peace, and bring glad tidings of good things! But they have not all obeyed the gospel. For Esaias saith, Lord, who hath believed our report? So then faith cometh by hearing, and hearing by the word of God. 

Salvation will still come to the unsaved when they will repent of their sins and turn to Jesus to be saved – Romans 10:9 That if thou shalt confess with thy mouth the Lord Jesus, and shalt believe in thine heart that God hath raised him from the dead, thou shalt be saved. 

Because of that, they will be universally hated (cf. v9–10) and many will desire to harm them during the days of their preaching. When that harm is attempted, they will react with miraculous power— fire will flow out of their mouth and devour their enemies. There is no reason to assume that this is not real, literal fire, since God has in the past used fire to incinerate His enemies (Lev. 10:2; Num. 11:1; 16:35; Ps. 106:17–18). Those who wish to harm the two preachers must be killed in this way because God does not want their preaching stopped until their ministry is complete and will judge with death those who try to halt it.

 MacArthur, J. F., Jr. (1999). Revelation 1–11 (p. 302). Chicago: Moody Press.