Synopsis of the Books of the Bible, by John Nelson Darby, [1857-62], at sacred-texts.com
Exodus Chapter 18
Up to this all was grace, though there were dependence and conflict. The murmurs of the people had only served to shew the riches of the grace of God, who displayed His sovereignty in giving them all they could desire; which appears so much the more striking, because afterwards the same desires, under the law, brought very bitter chastisements. At length, after this reign of grace, follows the order of divine government, what will be realised in the millennium (chap. 18), where the king in Jeshurun judges in righteousness, establishes order and government, the Gentiles eat and offer sacrifices with Israel, and acknowledge that the God of the Jews is exalted above all gods. All this was the acting of God's grace and power.
During the days of the deliverance of Israel Moses's wife had been sent away, as the church during the tribulation, and as the church will appear in the joy of Israel's deliverance, so now Zipporah appears again upon the scene, and we have not only Gershom, "a pilgrim in a foreign land," but a second son, Eliezer; "for," Moses said, "the God of my fathers was mine help, and delivered me from the sword of Pharaoh." The application of this to the future deliverance of Israel is too evident to require any lengthened explanation.