1)
About what was the Bris?
1.
Malbim: They accepted full Avodah, without other motivations.
2)
What was the Chok u'Mishpat?
1.
Rashi: He arranged for them the Chukim (Radak - and Mishpatim) in the Torah, and they accepted them. Radak - this is like "Sham Sam Lo Chok u'Mishpat" (Shemos 15:25)
2.
Radak: He made the rock and Alah witnesses about the Bris.
3.
Malbim: He made enactments and laws for the need of the land. He made 10 enactments (Brachos 48b).
