Sunan Abi Dawud, Hadith 4909 ⓘ
Salam ibn Miskin, quoting an old man who witnessed AbuWa'il in a wedding feast, said: They began to play, amuse and sing. He united the support of his hand round his knees that were drawn up, and said: I heard Abdullah (ibn Mas'ud) say: I heard the apostle of Allah say: Singing produces hypocrisy in the heart.
حَدَّثَنَا مُسْلِمُ بْنُ إِبْرَاهِيمَ، قَالَ حَدَّثَنَا سَلاَّمُ بْنُ مِسْكِينٍ، عَنْ شَيْخٍ، شَهِدَ أَبَا وَائِلٍ فِي وَلِيمَةٍ فَجَعَلُوا يَلْعَبُونَ يَتَلَعَّبُونَ يُغَنُّونَ فَحَلَّ أَبُو وَائِلٍ حَبْوَتَهُ وَقَالَ سَمِعْتُ عَبْدَ اللَّهِ يَقُولُ سَمِعْتُ رَسُولَ اللَّهِ صلى الله عليه وسلم يَقُولُ " الْغِنَاءُ يُنْبِتُ النِّفَاقَ فِي الْقَلْبِ " .
also referenced under: Hadith 4927 (DarusSalam) & Book 41, Hadith 4909 (USC-MSA)