Abdullah bin Sabu' said: It was said to Sayyiduna Ali (may Allah be pleased with him): "Will you not appoint someone as caliph?" He said: "No! I leave you in the same situation in which the Prophet (peace and blessings be upon him) left you."
Abu Ya'la recorded it, and its narrators are thiqat (trustworthy).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الخلافة / 9007