It seems like you are referring to Abraham Lincoln's Second Inaugural Address, delivered on March 4, 1865, towards the end of the American Civil War. In this address, Lincoln emphasizes the idea of reconciliation and healing for both the Union and the Confederacy, even as the war was coming to a close. He wanted to humanize the enemy and promote national unity, so he included both sides at the end of the Civil war.
I hope this helped!
~~~Harsha~~~