English resources/Dr Jekyll and Mr Hyde/Religion
Cain, Satan, God forgive us. The book uses the language of sin for what Jekyll does.

4 quotes, in the order they happen.
I incline to Cain's heresy
Utterson · Chapter 1: Story of the Door · secrecy · religion
Cain asked, am I my brother's keeper? Utterson says he lets people go their own way. He does not pry. Then he does.
I swear to God I will never set eyes on him again.
Jekyll · Chapter 5: Incident of the Letter · religion · secrecy
Jekyll swears he is done with Hyde. He means it. It does not hold.
God forgive us, God forgive us
Utterson · Chapter 7: Incident at the Window · religion · evil
After they see Jekyll's face change at the window, Utterson can only pray. Twice.
O God!" I screamed, and "O God!" again and again
Lanyon · Chapter 9: Dr Lanyon's Narrative · science · religion · duality
Lanyon watches Hyde drink the potion and turn into Jekyll. He cannot stop screaming.