Why does Proctor remind Mary Warren of the angel Raphael?

Mary Warren is a very unstable girl. She apears in court terrified of betraying Abigail. Proctor knows that Mary Warren could turn on him at any moment and not reveal the truth. Proctor tries to comfort her by using angel Raphael as an example of doing good despite being afraid: God will protect her.

"Remember what the Angel Gabriel say to the boy Tobias, Do that which is good and no harm can come to thee."

gcy