The last words of the grandfather in this short story to the narrator focus on something of a revelation and a disclosure, as they belie the way in which the grandfather has lived his life as a man who was "the meekest of men." However, as the rest of the story goes to show, the grandfather's advice and words are essential to ensure survivial in a world that is fundamentally opposed to the black man and mistreats him deliberately for the purpose of humour and delight for whites. Let us just remind ourselves briefly of the last words:
Son, after I'm gone I want you to keep up the good fight. I never told you, but our life is a war and I have been a traitor all my born days, a spy in the enemy's country ever since I give up my gun back in the Reconstruction. Live with your head in the lion's mouth. I want you to overcome 'em with yeses, undermine 'em with grins, agree 'em to death and destruction, let 'em swoller you till they vomit or bust wide open.
These words point towards the fundamental inequality between blacks and whites, and argue that the only way to really oppose racism and fight for equality is to pretent to agree with the status quo whilst at the same time living as a "spy" and having your "head in the lion's mouth" while you slowly and quietly work for change. The grandfather thus argues that there is no value in openly opposing the discrimination faced by blacks in their time. The only way to work for change is to be seditious in secret and to overtly go along with the inequality and discrimination whilst working secretly for change. This is advice that the rest of the story underlines.