1 YHWH spoke to Moses, “Go in to Pharaoh, and tell him, ‘This is what YHWH says, “Let my people go, that they may serve me. 2 If you refuse to let them go, behold, I will plague all your borders with frogs. 3 The river will swarm with frogs, which will go up and come into your house, and into your bedroom, and on your bed, and into the house of your servants, and on your people, and into your ovens, and into your kneading troughs. 4 The frogs shall come up both on you, and on your people, and on all your servants.”’” Exodus 8:1-4WEB
This passage contains a positive command, with immediate application directed toward Pharaoh through Moses, "Let my people go, that they may serve me". The command is followed by a description of the penalty which God intends to visit on Pharaoh if Pharaoh does not obey.
This command is part of the Principles and Definitions. It is relevant to an understanding of the distinctive role of Prophecy as Moses is relaying a message from God, and of Stewardship as God is commanding Pharaoh to relinquish God's possession Israel.
This command was fulfilled when Aaron and Moses spoke to Pharaoh and Israel in accordance with God's commands.