Caution: Translations of Quran and Ḥadīth may lead to possible misapplications and misinterpretations. This site is intended for students of sacred knowledge that are proficient in comprehending classical Arabic and have a strong foundation in Islamic sciences. Also note that religious injunctions rely on several aspects beyond what one may glean through reading individual aḥādīth.
Qurʾān Bukhārī Muslim Nasāʾī Abū Dāwūd Tirmidhī Ibn Mājah Mālik Aḥmad Dārimī Ḥākim Ibn Ḥibbān Ṭabarānī Nasāʾī's Kubrá Bayhaqī al-Luʾluʾ wa-al-Marjān Ibn Rajab's Fifty Riyāḍ al-Ṣāliḥīn Aḥmad's Zuhd Suyūṭī
muslim:593d – [Chain 1] Ḥāmid b. ʿUmar al-Bakrāwī > Bishr / Ibn al-Mufaḍḍal [Chain 2] Muḥammad b. al-Muthanná > Azhar > Ibn ʿAwn > Abū Saʿīd > And Rrād Kātib al-Mughīrah b. Shuʿbah

Mu'awiya wrote to Mughira (the contents) of the hadith as transmitted by Mansur and A'mash.  

مسلم:٥٩٣d – وَحَدَّثَنَا حَامِدُ بْنُ عُمَرَ الْبَكْرَاوِيُّ حَدَّثَنَا بِشْرٌ يَعْنِي ابْنَ الْمُفَضَّلِ ح قَالَ وَحَدَّثَنَا مُحَمَّدُ بْنُ الْمُثَنَّى حَدَّثَنِي أَزْهَرُ جَمِيعًا عَنِ ابْنِ عَوْنٍ عَنْ أَبِي سَعِيدٍ عَنْ وَرَّادٍ كَاتِبِ الْمُغِيرَةِ بْنِ شُعْبَةَ قَالَ

كَتَبَ مُعَاوِيَةُ إِلَى الْمُغِيرَةِ بِمِثْلِ حَدِيثِ مَنْصُورٍ وَالأَعْمَشِ