عنِ ابْن عمر رضِي اللّه عنْهُمَا أَنَّهُ سمِعَ رَجُلًا يَقُولُ: لا والكعْبةِ، فقالَ ابْنُ عُمر: لا تَحْلِفْ بِغَيْرِ اللّهِ، فإِني سَمِعْتُ رسُولَ اللّهِ صَلّى اللّهُ عَلَيْهِ وسَلَّم يقُولُ: «منْ حلفَ بِغَيْرِ اللّهِ، فَقدْ كَفَر أَوْ أَشرْكَ» رواه الترمذي وقال: حدِيثٌ حسَنٌ.
Ibn Umar (may Allah be pleased with them both) reported that he heard a man say: "No, by the Kaʿbah." So Ibn Umar said: "Do not swear by other than Allah, for I heard the Messenger of Allah (peace and blessings be upon him) say: 'Whoever swears by other than Allah has committed disbelief or shirk (associating partners with Allah).'" Reported by al-Tirmidhi, who said: a hasan (good) hadith.
الشرح · explanation
كَفر أَوْ أشركَ: هذا للزَّجرِ والتَّغليظِ في النَّهيِ والامتِناع عنْ مثلِ هذا الحلِفِ، وليسَ هذا شِركًا محضًا؛ فالحلفُ بغيرِ اللّهِ من الشِّركِ الأصغرِ وقدْ نَهَى عَنه الشرعُ؛ لأنَّه ذَريعةٌ إلى الشِّركِ الأكبرِ ووَسِيلةٌ للوُقوعِ فيهِ.
"Has committed disbelief or shirk": this is by way of rebuke and severe emphasis in the prohibition and in refraining from such swearing; it is not pure shirk. Swearing by other than Allah is minor shirk (al-shirk al-asghar), which the Sacred Law has forbidden, because it is a means leading to major shirk (al-shirk al-akbar) and a pathway to falling into it.
الدروس · lessons
النهي عن الحلف بغير اللّه تعالى وصفاته مطلقًا، فيدخل في النهي ما يكثر الناس الحلف به كالشرف والأولاد ورحمة أبيهم وغير ذلك، كما يدخل في ذلك الحلف بالأماكن المقدسة والأنبياء والصالحين وغيرهم. أنّ من حلف بغير اللّه تعالى وصفاته واعتقد أو قصد تعظيم المحلوف به كتعظيمه للّه تعالى فقد كفر.
The prohibition of swearing by other than Allah the Exalted and His attributes, absolutely. Included in the prohibition is what people often swear by, such as honor, children, the mercy [shown to] their father, and the like; likewise included is swearing by sacred places, the prophets, the righteous, and others. That whoever swears by other than Allah the Exalted and His attributes, and believes in or intends venerating the thing sworn by as he venerates Allah the Exalted, has committed disbelief.