Hunter's fuzzy guitar lines have been compared to the musical structure of Jimi Hendrix's "Castles Made of Sand" (1967). 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". The final two minutes of "The Root" feature an emphatic refrain of the chorus line. 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". In the promotional EPK for "Voodoo", D'Angelo discussed the therapeutic nature of recording "The Root", stating "It was kinda therapeutic for me to do this song. It kinda help me get over, because I'm so pathetic in the song. You know what I mean? That's what 'The Root' is. She got it on me. And I'm just fucked up. It was good for me to get over that. It was hard for me sometimes to do that song. To record it, because when doing it I would have to put myself in that mode you know". Music critic Neil Drumming of the "Washington City Paper" called "The Root" catchy and sexy. "The Cavalier Daily" writer John Bylander stated that the song has "an amazing baseline and chorus". One writer interpreted the song's theme as "some vengeful woman done worked a root on him". "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. Music writer Stephanie Zacharek of "Salon" stated that D'Angelo "takes pleasure in his very powerlessness in the face of womankind" on the song. "The Village Voice" writer Miles Marshall Lewis commended Charlie Hunter for his guitar work and D'Angelo for his lyrical substance on the song, writing that its lyrical narrative "can actually be digested and emotionally felt, sadly rare for Hot 97 R&B". "Spin" magazine's David Peisner wrote that the song suggests "a guy who's seen love's nasty side". "The GW Hatchet" called it "inspiring", "The Austin Chronicle" described it as "slow and measured", and "Exclaim!"