Kurdus narrates: Sayyiduna Khabbab (may Allah be pleased with him) was the sixth person to accept Islam, so he was a sixth of Islam.
Al-Tabarani recorded it as a mursal narration; its narrators up to Kurdus are the narrators of the Sahih, and Kurdus is thiqah (trustworthy).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب المناقب / 15629
Hadith Gradingمحدثین:إسنادہ مرسل،
Hadith Takhrij«اخرجه الطبراني فى المعجم الكبير (3613)»