"The Root" features intricate musical arrangements and its theme concerns a vengeful lover's effect on the song's narrator whose lament is depicted in the lyrics.
[3] A calm soul track,[8] "The Root" is performed in mid-tempo and its groove-based sound is accompanied by Charlie Hunter's signature guitar riffs,[9] which form the crux of the song's winding grooves.
[10] Hunter's fuzzy guitar lines have been compared to the musical structure of Jimi Hendrix's "Castles Made of Sand" (1967).
[11] A mid-tempo heartbreak song, the lyrics of "The Root" have the narrator lamenting a lost lover; "In the name of love and war, she took my shield and sword ... From the pit of the bottom that knows no floor/Like the rain to the dirt, from the vine to the wine/From the alpha of creation, to the end of all time".
Reveille Magazine's Steve McPherson wrote that the chorus "feeds back into itself over and over again, turning from a hook into a mantra into a gospel affirmation".
[13] NME compared the lyrics, in particular the line "My blood is cold/And I can't feel my legs", to the "weird possession stuff" of the album's voodoo concept.
[17] Music writer Stephanie Zacharek of Salon stated that D'Angelo "takes pleasure in his very powerlessness in the face of womankind" on the song.
[13] Spin magazine's David Peisner wrote that the song suggests "a guy who's seen love's nasty side".