Sayyiduna Jabir bin Abdullah (may Allah be pleased with them both) narrates that the Prophet (peace and blessings be upon him) said: "Whoever honours a Muslim ruler, it is as though he honours Allah Almighty."
Al-Tabarani recorded it in al-Mu'jam al-Awsat. Its chain contains Bahr bin Kathir, who is matruk (abandoned).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الأدب / 12627