The Messenger of Allah ﷺ said, "The most deserving of conditions to be fulfilled are those by which you have made intimate relations lawful."
أخبرنا عيسى بن حماد قال أنبأنا الليث عن يزيد بن أبي حبيب عن أبي الخير
عن رسول الله ﷺ قال إن أحق الشروط أن يوفى به ما استحللتم به الفروج
Bukhari reported it in the Book of Conditions, Chapter on Conditions Regarding the Dower at the Marriage Contract, no. 2721, from the hadith of Layth bin Saad, and Muslim, in the Book of Marriage, Chapter on Fulfilling Conditions in Marriage, no. 1418, from the hadith of Yazid bin Abu Habib, with the same chain.