The Messenger of Allah ﷺ said, "The most deserving of conditions to be fulfilled are those by which you have made intimacy lawful."
حدثنا يحيى بن سعيد عن عبد الحميد بن جعفر قال حدثني يزيد بن أبي حبيب عن مرثد بن عبد الله اليزني
قال رسول الله ﷺ إن أحق الشروط أن يوفى به ما استحللتم به الفروج
Its isnad is sahih, its narrators being reliable and well-known. The hadith was narrated by Bukhari 9/217, no. 5151, Fath al-Bari, in Nikah, "Conditions in Marriage," Muslim 2/1035, no. 1418, Tirmidhi 3/425, no. 1127, who graded it sahih, and Abu Dawud 2/244, no. 2139.