The verse says...

The verse says: “When they came against you from above you and from below you, and when the eyes swerved and the hearts reached to the throats, and you did imagine about Allah diverse thoughts,” Many of the commentators believe that the Arabic word /fauq/ (above) mentioned in this holy verse refers to the east of Medina wherefrom the tribe of Qatfan entered, and the word /’asfal/ (below) refers to the west of it wherefrom the tribe of Quraysh and their assistants came.

Of course, regarding to the fact that Mecca is located in the south of Medina, the pagans of Mecca must have come from the south, but perhaps the condition of the road and that of the arrival the gate of Medina were in a state that they had to turn round a part of the city and arrive from the west. However,