Riyad Us-Saliheen (Gardens of the Righteous)

Chapter 327
Prohibition of Obscenity

1734. Ibn Mas`ud (May Allah be pleased with him) said: The Messenger of Allah (PBUH) said, "A true believer does not taunt or curse or abuse or talk indecently.''
[At-Tirmidhi].

Commentary:  We learn from this Hadith that in order for one to be a perfect believer, it is not enough to possess all the moral qualities but one must also keep oneself away from moral evils.

1735. Anas (May Allah be pleased with him) said: The Messenger of Allah (PBUH) said, "Indecency does not leave anything untainted and decency does not leave anything ungraced and embellished.''
[At-Tirmidhi].

Commentary: This Hadith induces us to abandon indencency and adopt decency.