3.
The First Discourse on Verbal Misconduct
243.
"Monks, there are these five dangers of verbal misconduct. Etc.
benefits of good verbal conduct. Etc.
The third.
Paṭhamavacīduccarita Sutta [AN 5.243, PTS 3.267]
Also known as: Paṭhamavacīduccaritasuttaṃ