It is narrated from Hazrat Harith (may Allah be pleased with him) that the Prophet (peace and blessings of Allah be upon him) wrote a will for him (Harith, may Allah be pleased with him) in the name of the rulers who would come after him, and he also sealed it.
Hadith Referenceمسند احمد / مسند الشاميين / 18055
Hadith Gradingحکم دارالسلام:إسناده ضعيف لجهالة التابعي، وهو الحارث بن مسلم