Why might one of the two witnesses be Elijah?
Scripture does not name the witnesses, so this is speculation. One might be Elijah because he was taken up without having died. Another reason given is Malachi 4:5, which the teaching directs readers to consider. This identification is not dogmatic, since the verse itself does not say so-and-so.
Les explains that the two witnesses appear at the beginning of the tribulation in Revelation 11. He says we cannot be dogmatic because Scripture does not tell us who they are; the verse itself does not name them. He thinks one witness is easier to decide than the other, and that one is Elijah. His first reason is that Elijah was taken up without having died. He also directs listeners back to Malachi chapter 4, verse 5, and notes that Matthew chapter 11 is marked for later consideration. He presents the identification as possible speculation, not certainty.