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Just remember the text says it is the number of a man
The verse doesn't the beast is a man it only says he has the number of a man. We can't assume that the beast is a man just because the beast has the number of a man. Would you assume my dog is a man because he has the name of a man? So why assume that just because the number of the beast is the number of a man he must be a man. Doesn't Gods unchanging word tell us a beast is a kingdom? So why would you doubt what God's inspired word tells us in favor of a belief based on assumption?