Psalms 105:28

They rebelled not against his word - Instead of ולא מרו velo maru, "they rebelled," some think that a ש shin has been lost from before the word, and that it should be read ולא שמרו velo shamru, "they did not observe or keep his word." Or the words may be spoken of Moses and Aaron; they received the commandment of God, and they did not rebel against it. They believed what he had spoken, and acted according to his orders. It could not be spoken of the Egyptians; for they rebelled against his words through the whole course of the transactions.

He sent darkness, and made it dark - Exodus 10:21-23.

And they rebelled not against his word - More literally, "his words." The reference is to Moses and Aaron; and the idea, as expressed here, is that they were obedient to the command of God; that they went and did what he ordered them; that, although he required them to go before a mighty and proud monarch, to denounce against him the vengeance of heaven, and to be the instruments of bringing upon the land unspeakably severe judgments, yet they did not shrink from what God commanded them to do. They were true to his appointment, and showed themselves to be faithful messengers of God. Others, however, suppose that this refers to the Egyptians, and that it is to be taken as a question: "And did they not rebel against his word?" The language might bear this, and the translators of the Septuagint seem to have so understood it, for they render it, "And they rebelled against his words." But the most natural construction is that in our common version, and the design is evidently to commend the boldness and the fidelity of Moses and Aaron.

105:28 They - Moses and Aaron, who inflicted that plague after Pharaoh had threatened them.