If you were actually take the time to study the original text you would realize that the word "a" is not in the original Greek. Futurists use this verse as evidence that the beast is actually a human being. But what they overlook is that in contrast to what many people teach, 666 is the number of “man,” not the number of “a man.” There is no “a” in the original Greek. It was added by the translators, most of whom believed the Pope was thee antichrist. The Greek simply reads: gár (for) esti (it is) arithmós (number) anthrōpos (man) kai (and) hautou (his) arithmós (number) chi xi sigma (666).
Six is the number of man; it is the number of the flesh. 666 in some way illustrates the absolute hopelessness of those that have crossed over the line of reprobation. All those that have been reprobated have finally been given up to their own lusts, whereas those that are “in Christ Jesus … walk not after the flesh, but after the Spirit.” (Romans 8:1). It is they that refuse the mark of the beast and have their names “written in the book of life from the foundation of the world” (Revelation 17:8).