Sahih al-Bukhari, Volume 7, Book 62, Hadith 81 (USC-MSA) ⓘ
Narrated `Uqba: The Prophet said: "The stipulations most entitled to be abided by are those with which you are given the right to enjoy the (women's) private parts (i.e. the stipulations of the marriage contract).
حَدَّثَنَا أَبُو الْوَلِيدِ، هِشَامُ بْنُ عَبْدِ الْمَلِكِ حَدَّثَنَا لَيْثٌ، عَنْ يَزِيدَ بْنِ أَبِي حَبِيبٍ، عَنْ أَبِي الْخَيْرِ، عَنْ عُقْبَةَ، عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ " أَحَقُّ مَا أَوْفَيْتُمْ مِنَ الشُّرُوطِ أَنْ تُوفُوا بِهِ مَا اسْتَحْلَلْتُمْ بِهِ الْفُرُوجَ " .
also referenced under: Book 67, Hadith 86 (In-Book) & Hadith 5151 (DarusSalam)