1)
Why did he say "k'Chochmas Elakach Di vi'Ydach"?
1.
Rashi: You have more Chochmah of your G-d than the judges who judge the entire nation in Ever ha'Nahar.
2)
Why does it say "Shaftin v'Dayanin"?
1.
Malbim: Shofetim are experts. Dayanim are not experts - "l'Chol Yade'ei Dasei Elakach." Three commoners may judge, for surely at least one of them learned [monetary laws].
3)
What do we learn from "v'Di Lo Yada Tehode'on"?
1.
Rashi: A judge who does not know how to judge, teach to him Mishpat, to do it!
2.
Malbim: These are commoners - teach to them some laws.
