Riyad as-Salihin (The Meadows of the Righteous)
by Imam Nawawi
327. Chapter: On forbidding obscene and coarse language
1734. Ibn Mas'ud reported that the Messenger of Allah, may Allah bless him and grant him peace, said, "A believer is not a defamer, a curser, obscene or coarse." [at-Tirmidhi]
1735. Anas reported that the Messenger of Allah, may Allah bless him and grant him peace, said, "There is no obscenity in a thing without that marring it, and there is no modesty in a thing without that adorning it." [at-Tirmidhi]
