Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) narrates: Whenever someone died, the Prophet (peace and blessings be upon him) would say: "Send him on to our forerunner! And the best forerunner of my Ummah is Uthman bin Maz'un."
Al-Tabarani recorded it in al-Mu'jam al-Kabir, and something similar in al-Mu'jam al-Awsat. The chain of al-Mu'jam al-Kabir is da'if (weak), and the chain of al-Mu'jam al-Awsat contains narrators whom I do not know.
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب المناقب / 15656
Hadith Gradingمحدثین:إسنادہ ضعیف
Hadith Takhrij«اخرجه الطبراني فى المعجم الكبير (13160) ، أخرجه المعجم الكبير للطبراني برقم: 13160»