Family jewels big as fuck and I got the balls to say it
Family jewels is slang for male testicles aka the priceless jewels which brought about our very existence (shouts out to all the fathers). Also refers back to the last line as “mom’s jewelry” are jewels belonging to family.
Kendrick is playing on the double meaning of the word “balls” which can refer to both a man’s testes (for lack of a better term) and also a person who is courageous/brave.
This is indeed attested by the fact that Kendrick dropped the Control verse which shook the rap game up since he supposedly fired shots at a lot of rappers simultaneously, which can be considered a ballsy move.
To help improve the meaning of these lyrics, visit "BET Cypher 2013" by TDE (Ft. Ab-Soul, Isaiah Rashad, Jay Rock, Kendrick Lamar & ScHoolboy Q) Lyrics and leave a comment on the lyrics box