"Only One" begins with West singing, "as I lay me down to sleep, I hear her speak to me," in an apparant reference to his late mother Donda West, who died in 2007.
As the song unfolds, West imagines his mother telling him that she "never left you cause every road that leads to heaven's right inside you," and offering life advice like "the good outweighs the bad" and "you're not perfect but you're not your mistakes."
The song reaches its emotional apex when West sings about his daughter with Kardashian, North, who was born in June 2013. Kanye West again channels his mother, repeating several times to "tell Nori about me."
Kardashian told her millions of Twitter followers early Thursday that the song was her favorite by West and she cries every time she hears it.