Al-Miqdad reported: The Messenger of Allah, peace and blessings be upon him, said, “When you see those who flatter others, throw sand in their faces.”
Source: Ṣaḥīḥ Muslim 3002
Grade: Sahih (authentic) according to Muslim
Ibn Muflih said, “It is said that the Prophet meant by (throw sand in their faces) to express rebuttal and disapproval, as is said to a student who is repudiated.”
Source: al-Ādāb al-Shar’īyah 3/453
عن المقداد قَالَ قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ إِذَا رَأَيْتُمْ الْمَدَّاحِينَ فَاحْثُوا فِي وُجُوهِهِمْ التُّرَابَ
3002 صحيح مسلم كتاب الزهد والرقائق باب النهي عن المدح إذا كان فيه إفراط وخيف منه فتنة على الممدوح
قال ابن مفلح وَقِيلَ أَرَادَ بِهِ الرَّدَّ وَالْخَيْبَةَ كَمَا يُقَالُ لِلطَّالِبِ الْمَرْدُودِ
3/453 الآداب الشرعية والمنح المرعية