Musannaf Ibn Abi Shaybah 5344 — Sitting in ihtiba on Friday

Sayyiduna Ibn Umar (may Allah be pleased with them both) used to sit in the ihtiba' posture during the imam's khutbah. (Ihtiba' means that a person sits on his buttocks with his knees raised and clasps both hands around them for support, or ties a cloth around his back and knees. The Arabs often used to sit like this.)