Later in the evening following their lunch, Jack comes to understand about why Phoebe is alarmed about his not saying grace before eating. What does he realize grace means to Phoebe?

Jack realizes that if he does not sat grace, in Phoebe's eyes it would mean he does not believe in God. Phoebe might believe that if Jack no longer believes in God, then her brother David may not be in heaven and her father will not return to the family, and nothing will get better. The simple act of saying grace means much more to Phoebe than to Jack, who is struggling with his belief in God.