Joe Napalm:
Lincoln's words: "When I left Springfield I asked the people to pray for me. I was not a Christian. When I buried my son, the severest trial of my life, I was not a Christian. But when I went to Gettysburg and saw the graves of thousands of our soldiers, I then and there consecrated myself to Christ. Yes, I do love Jesus." [link]
Read carefully the above quote. When we read a quote from someone, we have three conclusions, maybe four:
1.) The individual quoted is telling the truth
2.) The individual quoted is lying (either knowingly or not)
3.) The individual quoted is with-holding information or leading the listener to a faulty conclusion (i.e., being deceptive)
[4.) The source of the quote is not reliable (either a miscopy of the quote, manipulation of the individuals original quote, etc.)]
Let us assume that the quote Joe gave up above comes from a reliable source (so we can ignore this conclusion).
Using my judgment, correct me if you think otherwise, Lincoln does not appear to be playing-it-safe with information. As a Christian, I know there is a time in a man's life that he can look back and say I was not a Christian. Lincoln appears to be quite candid, especially about giving information about his son. So I think we can neglect conclusion 3.
So we are now left with conclusion 1 or 2. It is up to your judgment on which one it is. But if you stand by conclusion 2 and demean or curse the man and in reality it was conclusion 1 (that he truly became a Christian), what do you think God thinks of your behavior? However, if you take his word (conclusion 1) and in reality he was lying (knowingly or not) what harm is your ignorance?
Coming to either conclusion with absolute certainty is difficult because when we look into the past we only see snap shots at various times. But if we align Lincoln's quotes up chronologically and transpose this ontop of a timeline, we can get a fairly accurate portrayal of this man's life.