MN 12: Māhasīhanāda Sutta (The Greater Discourse on the Lion’s Roar)
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A disrobed monk, Sunakkhata, attacks the Buddha’s teaching because it merely leads to the end of suffering. The Buddha counters that this is, in fact, praise, and goes on to enumerate his many profound and powerful achievements.
For a short series of lectures on this sutta by Bhikkhu Bodhi, see The Tathāgata in the MN.