937Al-Adab Al-MufradSahih (Al-Albani)وَعَنِ ابْنِ عَوْنٍ، عَنْ أَنَسِ بْنِ سِيرِينَ قَالَ: كَتَبْتُ لِابْنِ عُمَرَ، فَقَالَ: اكْتُبْ بِسْمِ اللهِ الرَّحْمَنِ الرَّحِيمِ، أَمَّا بَعْدُ: إِلَى فُلانٍ.Anas ibn Sirin said, "I wrote for Ibn 'Umar and he said, 'Write:"In the Name of Allah, the All-Merciful, Most Merciful. Following on from that: To so-and-so."'"Reference: Al-Adab Al-Mufrad 1125 In-book : Book 45, Hadith 9 English translation : Book 45, Hadith 1125