Songfacts®:

• Kendrick Lamar's "The Heart" series of songs dates back to April 2010 when he dropped "The Heart Pt. 1" on YouTube. "The Heart, Pt. 2" appeared on his O.verly D.edicated mixtape later that year. "The Heart Pt. 3 (Will You Let It Die?)," featured Jay Rock and Ab-Soul, and was released on SoundCloud just two days before 2012's good kid, m.A.A.d. city was made available.
• Throughout the song, K. Dot is spitting flames. He takes aim at deceitful politicians and fake news and specifically throws Donald Trump into the mix. ("Donald Trump is a chump, know how we feel, punk. Tell 'em that God comin'").
• At the heart of the song is a blatant diss that puts an unnamed rapper on notice
  
  My fans can't wait for me to son ya punk ass and crush your whole lil s--t
  I'll Big Pun ya punk ass, you a scared little bitch
  Tiptoein' around my name, nigga ya lame
  And when I get at you homie don't you just tell me you was just playin'.
  
  The rhymes sent social media ablaze with theories as to exactly Lamar is taking on. Some speculated that the Compton rapper is directing his hate towards Drake. There have been rumors that Kendrick and Drizzy haven't seen eye-to-eye since K. Dot's challenge to Hip-Hop's big guns, including Dreezy, to raise their game on the 2013 Big Sean track "Control." Following Lamar's rhymes on that cut, the pair are believed to have exchanged several subliminal jabs.
  
  However, the consensus seems to be that it's actually Big Sean that Lamar is addressing. On 2016's "No More Interviews" the Detroit MC spat lines which were suspected were aimed at K. Dot.
  
  And I can't lie like I like this s--t like I usually do
  And I'm just not impressed by you niggas rapping fast
  Who sound like one big asthma attack but trash when I'm rapping it back
  Who you put in your top five and claim they the savior of rap.
  
  Lamar's use of Big Sean's catchphrase, "lil bitch" as part of his diss further suggest that these lines are aimed at the G.O.O.D. Music rapper.
• The chorus is an interpolation of James Brown's song "Don't Tell A Lie About Me and I Won't Tell the Truth on You," which is a track from the Godfather of Soul's 1974 album Hell. Lamar is warning anyone he catches spreading falsehoods about him and his talents, he will reveal the truth about theirs.
  
  It has been suggested that the Compton rapper may be referencing the ghostwriting accusations that several rappers, including Drake, have been caught up in.
• The uncredited backing vocals on the hook are provided by El Paso singer Khalid, who at the time of this song's release was blowing up with his single "Location." Khalid's contribution arose from a song he was working on that he later scrapped. Producers turned it into a beat and said it "sounded like something that would be for Kendrick".
  
  "And he heard it," Khalid recalled to The Independent. "I'm freaking out. and he cuts the song, I didn't know until the single came around. And when I heard it I was like, 'no way'. He's such an amazing creative, I'm blessed to say that I was even a part of it."
• The song ends with a strong hint that Lamar could be dropping his fourth album on April 7, 2017, much like he did at the end of "The Heart Pt. 3" in 2012. "Y'all got till April the 7th to get ya'll s--t together," he raps teasingly.
  
  It turned out there'd been a week-long extension granted as on April 7th Lamar announced that the album would be released on April 14th.