Matthew 4:8 Again, the devil taketh him up into an exceeding high mountain, and sheweth him all the kingdoms of the world, and the glory of them...
This verse in Matthew by no means implies a flat earth, nor a monstrous mountain large enough to oversee the earth. Indeed, I have always thought that the trip to the mountain was a psychological ploy by Satan -- indeed, given what we know of the honor and shame dialectic of that social world, it fits as the premise of an "honor challenge" by placing Jesus in a pre-eminent position -- and that the showing of the kingdoms was accomplished by means of projecting images of some sort, as on a computer screen.
Indeed, this is suggested by the parallel verse in Luke 4:5 -
The devil led him up to a high place, and showed him in an instant all the kingdoms of the world.
However, as anyone who has climbed mountains knows - and the writer of Matthew surely knew, if he lived in the area around Judaea, as Matthew did - the higher up you go, the smaller things down below get, by your perspective. So it seems unlikely that (even if he did believe it a flat earth, personally) Matthew's offering is not compatible with a globe.
Note that even on a flat earth, a high mountain would be a very poor place to observe the kingdoms of the world "in their glory." Furthermore, if Matthew was implying that a mountain existed from which all the world was visible, then obviously, the mountain would be visible from all parts of the world. It is ludicrous to suggest that Matthew believed such a mountain existed.