Al-Adab Al-Mufrad 1126
Anas ibn Sirin said, "A man wrote in the presence of Ibn 'Umar,
'In the Name of Allah, the All-Merciful, Most Merciful, to so-and-so.'
Ibn 'Umar forbade him and said, 'Say:
'In the Name of Allah. It is for
Him.'"
وَعَنِ ابْنِ عَوْنٍ، عَنْ أَنَسِ بْنِ سِيرِينَ قَالَ‏:‏ كَتَبَ رَجُلٌ بَيْنَ يَدَيِ ابْنِ عُمَرَ‏:‏ بِسْمِ اللهِ الرَّحْمَنِ الرَّحِيمِ، لِفُلاَنٍ، فَنَهَاهُ ابْنُ عُمَرَ وَقَالَ‏:‏ قُلْ‏:‏ بِسْمِ اللهِ، هُوَ لَهُ‏.‏