Kweli the truth, like I'm comin' out the mouths of babes
Kweli is referring to the fact that his middle name (which is Kweli) means “truth” in Swahili, while Talib means “seeker”. See Kweli’s wikipedia page.
“Out of the mouths of babes” come the most honest things—kids are often the most candid because they aren’t afraid to offend you.
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