Narrated by Sayyidah Aisha (may Allah be pleased with her) that the Messenger of Allah (peace and blessings be upon him) said: Every condition that is not in the Book of Allah is rejected, even if people make a hundred such conditions.
Hadith Takhrij«أخرجه البخاري: 2561، ومسلم: 1504 ، (انظر مسند أحمد ترقيم الرسالة: 25504 ترقیم بيت الأفكار الدولية: 26019»
Brief Explanation
Benefits: … What is meant by “not being in the Book of Allah” is that the condition is contrary to the Book and Sunnah, i.e., due to this condition, something that is permissible in the Shari‘ah is rendered prohibited, or something that is prohibited by the Shari‘ah is rendered permissible. For example, at the time of marriage, if the woman’s guardians stipulate the condition that if the husband divorces this woman, he will have to pay such-and-such amount or give such-and-such monthly maintenance, this condition is unlawful (haram), because the right that the Shari‘ah has given to the husband to issue divorce is being restricted through this condition.