Why does it say "uv'Mayim Rabim Zera Shichor"?
Rashi: Zera came to Tzor from Egypt, which is on the Shichor river. Shichor is the Nile - "Min ha'Shichor Asher Al Pnei Mitzrayim" (Yehoshua 13:3).
Radak: The verse should be re-arranged. Zera Shichor which is in Mayim Rabim 1 [
This is Kli Paz' text of Radak.
What is "Ketzir Ye'or [Tevu'asah]"?
Rashi: The harvest of the river of Egypt, was the grain of Tzor. Radak - Egypt had much grain, because it does not need rain. The river irrigates the land.
Malbim: They exported grain special for seeding, and they also sold it with its chaff and ears; this is Ketzir Ye'or.
Why does it say "va'Tehi Sechar Goyim"?
Rashi: From the large nation that was in it, all the nations brought to it merchandise.