Musannaf Ibn Abi Shaybah 7767 — Praying behind rulers

Umayr bin Hani' said: When al-Hajjaj bin Yusuf was besieging Sayyiduna Ibn al-Zubayr (may Allah be pleased with him), the house of Sayyiduna Ibn Umar (may Allah be pleased with them both) was between al-Hajjaj and Ibn al-Zubayr. He would sometimes pray with Ibn al-Zubayr and sometimes with al-Hajjaj.