Riyad as-Saliheen 1578
Abu Hurairah (May Allah be pleased with him) said:
The Messenger of Allah ﷺ said, "Two matters are signs of disbelief on the part of those who indulge in them: Defaming and speaking evil of a person's lineage, and wailing over the dead."
[Muslim].
وعن أبي هريرة رضي الله عنه قال: قال رسول الله ﷺ :
" اثنتان في الناس هما بهم كفر: الطعن في النسب، والنياحة على الميت" ((رواه مسلم)).
Classification
Sahih (Authentic)
References
Riyad as-Saliheen 1578
Riyad as-Saliheen Book of Prohibited actions, Hadith 68