The Fifteenth Amendment had a significant loophole: it did not grant suffrage to all men, but only prohibited discrimination on the basis of race and former slave status. States could require voters to pass literacy tests or pay poll taxes - difficult tasks for the formerly enslaved, who had little education or money.
If you mean the speech to the Virginia Convention, then he builds ethos through religious passion. He portrays himself as a faithful Christian who is fighting for God. The allusion to the Biblical motif of light is the equivalent of fighting for God's truth.
They believed the war would be over by Christmas but it got proven wrong because of the enhanced technology during world war 1 and the use of trenches.
Hope this helped!
