It is true the Bible is complete and final as Brother Eli is projecting, but not in absolute terms. I have a feeling that Rev.22:18 is referring to the prophecies of Revelation in particular. This is because it says "...words of this prophecy..."
I'm saying this bearing in mind that I believe that God is still saying something to human race through prophecies, signs and events. I'm thinking that God is not only talking to people in written form. To support this view, Heb. 1:2 as quoted by Brother Eli says God was talking in "divers manners".