Exodus 18 · a question people ask
Did Jethro come before or after the law was given at Sinai?
Exodus sets the visit in the wilderness where Moses "was encamped, at the Mountain of God" (18:5), and then says Israel came "into the wilderness of Sinai" (19:1). Moses already says, "I make them know the statutes of God, and his laws" (18:16). In Deuteronomy, Moses tells of making "captains of thousands, captains of hundreds, captains of fifties, captains of tens" (Deuteronomy 1:15), "at that time" (Deuteronomy 1:9), after the LORD said at Horeb, "You have lived long enough at this mountain" (Deuteronomy 1:6). Christians read the order in two main ways. Both agree on what Jethro advised and that Moses "did all that he had said" (18:24).
How Christians read it
Where Christians differ, Favor sets out the main views side by side and doesn't pick one.
Told in the order it happened
Those who hold this view note that Israel was already near Horeb: at Rephidim the LORD said, "I will stand before you there on the rock in Horeb" (17:6), and 18:5 says Moses was "at the Mountain of God". At Marah, "There he made a statute and an ordinance for them" (15:25), and over the manna the LORD said, "How long do you refuse to keep my commandments and my laws?" (16:28). So Moses could teach "the statutes of God, and his laws" (18:16) before chapter 20.
Exodus 15:25 · Exodus 16:28 · Exodus 17:1 · Exodus 17:6 · Exodus 18:5 · Exodus 18:16
Told here, done later
Those who hold this view point to Deuteronomy, which sets the choosing of the captains at the time Israel was told to leave Horeb (Deuteronomy 1:6-15), and to Numbers, where Moses asks Hobab to come with Israel as they set out from the wilderness of Sinai (Numbers 10:11-12, 29). They read Exodus 18 as told ahead of its time, before the account of Sinai begins (19:1).
Deuteronomy 1:6-15 · Numbers 10:11-12 · Numbers 10:29 · Exodus 19:1
The verses
“Jethro, Moses’ father-in-law, came with Moses’ sons and his wife to Moses into the wilderness where he was encamped, at the Mountain of God.”
“When they have a matter, they come to me, and I judge between a man and his neighbor, and I make them know the statutes of God, and his laws.””
“So Moses listened to the voice of his father-in-law, and did all that he had said.”
“In the third month after the children of Israel had gone out of the land of Egypt, on that same day they came into the wilderness of Sinai. When they had departed from Rephidim, and had come to the wilderness of Sinai, they encamped in the wilderness; and there Israel encamped before the mountain.”