Not to mention, I have yet to look up the letter from Greeley that Abe was responding to.
The "Prayer of Twenty Millions" was an open letter published in the paper. Probably, Greeley also sent a copy to Lincoln. You can find it here.
A lot of Lincoln's literary fame may have to do with his ability to condense his thoughts into a few well chose words, rather than to sprawl out as Greeley does.
Thanks for providing the link. It was a very good read. Greeley provides so much context to the Conflict. He goes as far as to mention, "persistent, malignant traitors, who for twenty years have been plotting and for sixteen months have been fighting to divide and destroy our country."
Lincoln did not engineer the War.