Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) reports that the Prophet (peace and blessings be upon him) said: "The honour of a letter is that it be sealed."
This narration was recorded by Imam al-Tabarani in al-Mu'jam al-Awsat. Its chain contains a narrator, Muhammad bin Marwan al-Suddi al-Saghir, who is matruk (abandoned).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الأدب / 13176
Hadith Gradingمحدثین:ضعیف جداً
Hadith Takhrij«أخرجه المعجم الأوسط للطبراني برقم: 3884»