Bliss Chain

So I just came across this part in CoLS:

• Maryse Lightwood: I just know that every time the map flickers, I know he's alive...for now. And it's like I can breathe again, just for a little while.
• Brother Zachariah: I can understand that. There is little more powerful than the love of family. But what I do not know is why you chose to show this to me.
• Maryse: I know I should show it to the Clave. But the Clave knows of his bond with Jonathan now. They are hunting them both. They will kill Jace if they find him. And yet to keep it to myself is surely treason. I decided that telling you, the Brothers, was something I could bear. Then it is your choice whether to show it to the Clave. I--I can't stand that it be mine.
• Brother Zachariah: Your map tells you that your son is still alive. If you give it to the Clave, I do not think it will help them much, besides telling them that he is traveling fast and is impossible to track. They know that already. You keep the map. I will not speak of it for now.
• Maryse: But...you are a servant of the Clave...
• Brother Zachariah: I was once a Shadowhunter like you. I lived like you do. And like you, there were those I loved enough to put their welfare before anything else--any oath, any debt.
• Maryse: Did you...did you ever have children?
• Brother Zachariah: No. No children.
• Maryse: I'm sorry.
• Brother Zachariah: Do not be. And try not to let fear for Jace devour you. He is a Herondale, and they are survivors--
• Maryse: He is not a Herondale. He is a Lightwood. Jace Lightwood. He's my son.
• Brother Zachariah: (pause) I did not mean to imply otherwise.