Spike and Angelus in “Innocence”

Now, I know you haven't been in the game for a while, mate, but we still do kill people. Sort of our raison d'être, you know.

Spike, my boy, you really don't get it, do you? You tried to kill her, but you couldn't. Look at you. You're a wreck! She's stronger than any Slayer you've ever faced. Force won't get it done. You gotta work from the inside. To kill this girl ... you have to love her.