What did Yisro mean when he advised Moshe to warn the people about the Chukim and the Toros?
Ramban: To issue them with a strict warning about keeping the Mitzvos and about the punishments that are due for not keeping them.
What do all the seemingly vague statements ("v'Hodata Lahem Es ha'Derech ... ") really mean?
Targum Yonasan: "V'Hodata Lahem "- to pray in the Beis ha'Keneses; 1 "Es ha'Derech - to visit the sick; "Yeilchu bah" - to bury the dead and to perform Chesed; "ve'Es ha'Ma'aseh" - to carry out Din; "Asher Ya'asun" - to go Lifnim mi'Shuras ha'Din" with the Resha'im.
The Gemara in Bava Kama (99a) which expounds the Pasuk along similar lines, interprets "v'Hodata Lahem" as 'Zeh Beis Chayeihem', which Rashi there explains to mean to study Torah, whereas in Bava Metzi'a, 30b) he says to earn a livelihood.