What did Moses call the assembly just before he struck the rock at Meribah?

Answer: Rebels

Moses said, "Listen now, you rebels, must we bring you water out of this rock?" Then he raised his hand and struck the rock.

“Then Moses and Aaron gathered the assembly in front of the rock, and Moses said to them, “Listen now, you rebels, must we bring you water out of this rock?” Then Moses raised his hand and struck the rock twice with his staff, so that a great amount of water gushed out, and the congregation and their livestock were able to drink.”— Numbers 20:10-11 (BSB)