Sahih al-Bukhari 2721
Book 54: Conditions · Narrated by `Uqba bin Amir
Arabic
حَدَّثَنَا عَبْدُ اللَّهِ بْنُ يُوسُفَ، حَدَّثَنَا اللَّيْثُ، قَالَ حَدَّثَنِي يَزِيدُ بْنُ أَبِي حَبِيبٍ، عَنْ أَبِي الْخَيْرِ، عَنْ عُقْبَةَ بْنِ عَامِرٍ ـ رضى الله عنه ـ قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " أَحَقُّ الشُّرُوطِ أَنْ تُوفُوا بِهِ مَا اسْتَحْلَلْتُمْ بِهِ الْفُرُوجَ ".
English translation
Narrated `Uqba bin Amir:Allah's Messenger (ﷺ) said, "From among all the conditions which you have to fulfill, the conditions which make it legal for you to have sexual relations (i.e. the marriage contract) have the greatest right to be fulfilled
Reference: Sahih al-Bukhari 2721, Book of Conditions. English translation by Dr. Muhammad Muhsin Khan.