Dick Turpin, Season 1, Episode 8. The Upright Man
Dick Turpin: To the upright man!
Tyson Sarney: Dick! By Heaven! Oh, thank God you're back! We thought you'd been captured.
Dick Turpin: And the wish is often father to the thought.
(which means that the thought is born from the wish, because the "upright" man has betrayed Turpin and he's astonished to see him back)
(upright: always behaving in an honest way)
To learn more about this saying do visit the english club related page.