Your guess: "angels" or "ages?"

[Angela]

Since the original question asked for a guess - mine would be "ages", simply because I did not come across anything yet that depicted Stanton as a very religious person. He seemed to have dealt with personal tragedy in a manner that is little recorded other than that he changed as a person. Also, he just doesn't strike me as a person to even ever use the word "angels" and especially not on the occasion mentioned.
As I'm trying to picture the moment, he was probably worried a lot about public perception of the events of that night and how they would play out. He was probably fearing riots, an uprising of the southern states, chaos in Washington...this might have led to that particular quote. Maybe he was relieved that he did not have to deal with Lincoln's public perception anymore, knowing that he had only one way to go?