“"What makes you think that Valentine's change of plans had anything to do with your brother?"
"Because only Jace can piss someone off that much."”

“I'm not sure anyone can make Jace do anything. But I think you can remind him that he has something to live for.”

“You have a dark heart in you, Valentine’s daughter,” he said. “You just won’t admit it. And if you want Jace, you had better accept it. Because he belongs to me now.”

“If you don't design your own life plan, chances are you'll fall into someone else's plan. And guess what they have planned for you? Not much.”

“But the Silent Brothers have tried everything to separate Jace from the heavenly fire, and they can't do it. It's in his soul. So what's their plan, hitting Sebastian over the head with Jace until he passes out?”

“You can always change your plan, but only if you have one..”

“Jace looked as if she had slapped him. "Why are you determined not to believe us?"
"Because she loves you," said Valentine.
Clary felt the blood drain out of her face.”

“It's like you have a plan and someone comes along and makes you want to change it all, but you still like your first plan, no matter how fantastic the second one makes you feel.”

“And I don’t see how Sebastian can be all that fond of Jace, either. He was horribly jealous of him all his life. He thought Jace was Valentine’s favorite,” added Clary.
“Not to mention,” Magnus noted, “that Jace killed him. That would put anyone off.”

“I was scared. Do you know what it's like to hold someone else's life in
your hands? It's like playing God. Can you think of anything scarier than
that?”