Mishkat al-Masabih 23 Medicine and Spells كتاب الطب والرقى 37

وَعَنِ الزُّهْرِيِّ مُرْسَلًا عَنِ النَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «مِنْ احْتَجَمَ يَوْمَ الْأَرْبِعَاءِ أَوْ يَوْمَ السَّبْتِ فَأَصَابَهُ وَضَحٌ فَلَا يَلُومَنَّ إِلَّا نَفْسَهُ» . رَوَاهُ أَحْمَدُ وَأَبُو دَاوُدَ وَقَالَ: وَقَدْ أسْند وَلَا يَصح

Zuhri reported in mursal form that the Prophet said: “If anyone has himself cupped on a Wednesday or a Saturday and is smitten by leprosy, he must blame no one but himself .” Ahmad and Abu Dawud transmitted it. It has been given an isnad , but Abu Dawud said that that is not sound;