Lincoln grew in his faith during the war and saw God's hand in it.
I'll need to re-borrow said book from my local library however my notes indicate the following quotes from Ms. Goodwin's book:
"Lincoln’s inability to take refuge in the concept of a Christian heaven."
Regarding the deaths of those close to him she wrote that he: "confronted the loss of loved ones without prospect of finding them in the afterlife."
I'll get back to you with the appropriate page numbers as soon as I can.