I don’t know what to do,” Will said. “Mortmain has taken Tessa, and I believe now I know where she might be. There is a part of me that wants nothing more than to go after her. But I cannot leave Jem. I swore an oath. And what if he wakes in the night and finds I am not here?” He looked as lost as a child. “He will think I left him willingly, not caring that he was dying. He will not know. And yet if he could speak, would he not tell me to go after Tessa? Is that not what he would want?” Will dropped his face into his hands. “I cannot say, and it is tearing me in half.
Cassandra Clare (2014). “Clockwork Princess”, p.235, Simon and Schuster