Full Idea
It is not necessary for what moves things to be itself moving. For a thing can be moving in two ways - with reference to something else, or intrinsically. A ship is moving intrinsically, but sailors move because they are in something that is moving.
Gist of Idea
Movement can be intrinsic (like a ship) or relative (like its sailors)
Source
Aristotle (De Anima [c.329 BCE], 406a03)
Book Reference
Aristotle: 'De Anima (on the psuche)', ed/tr. Reeve, C.D.C. [Hackett 2017], p.9
A Reaction
I love the way that Aristotle is desperate to explain the puzzle of movement, yet we just take it for granted. Very illuminating about puzzles. Newton's First Law of Motion.