One person. All it takes is one person."
-Severus Snape

SCORPIUS: A doe? Lily’s Patronus.
SNAPE: Strange, isn’t it? What comes from within.

Harry Potter told his son you’re a great man. [...] He said you were the bravest man he’d ever met. He knew, you see — he knew your secret — what you did for Dumbledore. And he admired you for it — greatly. And that’s why he named his son — my best friend — after you both. Albus Severus Potter.

If I had to choose a companion to be at the return of eternal darkness with, I'd choose you.

Tell Albus - tell Albus Severus - I'm proud he carries my name.

One person. All it takes is one person. I couldn’t save Harry for Lily. So now I give my allegiance to the cause she believed in. And it’s possible — that along the way I started believing in it myself.