'Certain Man' in the Bible

And He said, "Go into the city, to a certain man, and say to him, 'The Teacher says, "My time is near. I am going to keep the Passover at your house with my disciples."'"

Here is scope for wisdom! Let anyone who has the mental keenness calculate the number of the wild beast, for it is the number of a certain man; his number is six hundred and sixty-six.