One morning, a man approaches Jerry at the stable and asks if he could hire Jerry regularly to drive to church on Sundays since his wife can't walk that far. Jerry tells him he doesn't have the right sort of driving license, and the man—Mr. Briggs, we're assuming—tells Jerry that it wouldn't be a problem, and "Mrs. Briggs very much prefers you to drive her" (36.4).
Jerry insists that a seven-day license is too exhausting, but Mr. Briggs continues to press Jerry, so Jerry busts out a lengthy, Bible-quoting explanation of why he won't drive on Sundays. At last, Briggs gives up.
Jerry calls for his wife and tells her what's just happened, and asks her if he should have sacrificed his Sunday rule for this particular customer. Polly says she'd rather have him home on Sundays, even if Briggs agreed to give Jerry a sovereign once a week. She starts to get upset, and Jerry assures her he's told Briggs he'd never do it.
This results in Jerry losing Mr. Briggs, who was his best customer, so his work gets a little bit harder. Which leads to a lively debate among the cab drivers about the merits of religion and working on Sundays. Jerry says religion is all about the way you behave, saying, "Real religion is the best and truest thing in the world and the only thing that can make a man really happy, or make the world any better" (36.24).