Muwatta Malik 1148
موطأ مالك#1148SahihThese are the words of a Successor — the generation after the Companions — not of the Prophet ﷺ.
وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ يَحْيَى بْنِ سَعِيدٍ، عَنْ سَعِيدِ بْنِ الْمُسَيَّبِ، أَنَّهُ قَالَ ثَلاَثٌ لَيْسَ فِيهِنَّ لَعِبٌ النِّكَاحُ وَالطَّلاَقُ وَالْعِتْقُ .
Yahya related to me from Malik from Yahya ibn Said that Said ibn al-Musayyab said, "There are three things in which there is no jest:marriage, divorce, and setting free
Scholarly Authentication
The label above is the grade most of these scholars gave — one dissenting opinion no longer speaks for all of them. If any scholar calls a narration fabricated, that verdict is shown instead, whatever the others say. Each scholar's own wording:
Salim al-HilaliMaqtu Sahih
In-book reference: 28:58