They couldn't even hold a candle if they Buddhist
Not being able to “hold a candle” to someone is an idiom meaning that you can’t come close to achieving that someone’s quality or skill. Candles are also part and parcel of many Buddhist rituals, and thus a Buddhist would presumably be very proficient at holding candles. But still, even if “they” (other rappers, probably) were Buddhist, they still wouldn’t be able to hold a candle to Kool AD’s rap skills.
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