… is from Charles Davenant‘s 1697 tract An essay on the East-India trade, as quoted on page 99 of Jacob Viner‘s 1937 collection Studies in the Theory of International Trade:
Trade is in its nature free, finds its own channel and best directeth its own course; and all laws to give it rules and directions, and to limit and circumscribe it, may serve the particular ends of private men, but are seldom advantageous to the public.
