בראשית יא:ג פירוש: רש״י, ספורנו, רד״ק והעמק דבר

איש אל רעהו ONE TO ANOTHER — One nation to the other: Mizraim to Cush, Cush to Put. and Put to Canaan (Genesis Rabbah 38:6).

הבה נלבנה לבנים, now they wanted to build permanent housing for themselves and pens for the flocks and herds. This was a common consensus, as we know from the Torah describing their speaking to each other as ויאמרו איש אלך רעהו, “they said each to his colleague.”

ויאמרו..הבה, this word הבה, is customarily used in connection with a plan forming. It describes more a firm suggestion than a definite order, command. This is one of the reasons this word is always found in the feminine mode, and followed by a plural mode.