Jamieson, Fausset and Brown on Exodus 18:12

12. Jethro ... took a burnt offering--This friendly interview was terminated by a solemn religious service--the burnt offerings were consumed on the altar, and the sacrifices were peace offerings, used in a feast of joy and gratitude at which Jethro, as priest of the true God, seems to have presided, and to which the chiefs of Israel were invited. This incident is in beautiful keeping with the character of the parties, and is well worthy of the imitation of Christian friends when they meet in the present day.