He foresees the outcome of the war because: Lincoln spoke of the nation as a whole, a new birth of freedom, and the goals of the North. He also spoke of the government in terms of all the people
He see the distant behavior from the Southern States as a threat to the unity of the nation, and he believed that if the northern states unite, they could take the south and reformed it into a more progressive state.
And he is correct aboout the result, The Union indeed won the war.