(Jace is about to kill a demon…)

Clary Fairchild: Stop! You can’t do this.

Alec Lightwood: What’s this?

Jace Herondale: It’s a girl. Surely you’ve seen girls before, Alec. Your sister Isabelle is one.

From the book The Mortal Instruments: City of Bones (Book One) | Written by Cassandra Clare