And Moses stretched forth his hand toward heaven; and there was a thick darkness in all the land of Egypt three days:Exodus 10:22 Parallel Commentaries

Exposition of Chap. Iii. (ii. 28-32. )
Ver. 1. "And it shall come to pass, afterwards, I will pour out My Spirit upon all flesh; and your sons and your daughters shall prophesy; your old men shall dream dreams, and your young men shall see visions." The communication of the Spirit of God was the constant prerogative of the Covenant-people. Indeed, the very idea of such a people necessarily requires it. For the Spirit of God is the only inward bond betwixt Him and that which is created; a Covenant-people, therefore, without such an inward …
Ernst Wilhelm Hengstenberg—Christology of the Old Testament

Exodus
The book of Exodus--so named in the Greek version from the march of Israel out of Egypt--opens upon a scene of oppression very different from the prosperity and triumph in which Genesis had closed. Israel is being cruelly crushed by the new dynasty which has arisen in Egypt (i.) and the story of the book is the story of her redemption. Ultimately it is Israel's God that is her redeemer, but He operates largely by human means; and the first step is the preparation of a deliverer, Moses, whose parentage, …
John Edgar McFadyen—Introduction to the Old Testament