مُوَطَّأُ مَالِكٍ
Muwatta Malik 1151
Marriage
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."
Arabic/English book reference: Book 28, Hadith 56