It was narrated from 'Utbah bin 'Amir that the Messenger of Allah said:

"The conditions that are most deserving of fulfillment, are those by means of which the private parts become allowed to you."

أَخْبَرَنَا عِيسَى بْنُ حَمَّادٍ، قَالَ أَنْبَأَنَا اللَّيْثُ، عَنْ يَزِيدَ بْنِ أَبِي حَبِيبٍ، عَنْ أَبِي الْخَيْرِ، عَنْ عُقْبَةَ بْنِ عَامِرٍ، عَنْ رَسُولِ اللَّهِ ﷺ قَالَ " إِنَّ أَحَقَّ الشُّرُوطِ أَنْ يُوَفَّى بِهِ مَا اسْتَحْلَلْتُمْ بِهِ الْفُرُوجَ " .