Al-Matalib al-'Aliyah 3724 — Surah Qaf

It is narrated from Abu Mijlaz (may Allah have mercy on him) that Sayyiduna Umar bin al-Khattab (may Allah be pleased with him) lay on his back in one of the gardens of Madinah and placed one of his feet on the other. In fact, the Jews used to fabricate lies against Allah, the Mighty and Majestic, saying: "Indeed, Allah, the Blessed and Exalted, finished creating the creation on Saturday and then rested." At this Allah, the Mighty and Majestic, revealed this statement: "And We certainly created the heavens and the earth and whatever is between them in six days, and no weariness touched Us" [Surah Qaf: 38]. So some people disliked placing one foot on the other (to avoid resembling this false belief of the Jews), until Sayyiduna Umar (may Allah be pleased with him) himself did it.
Imam Ishaq bin Rahwayh (may Allah have mercy on him) said that al-Nadr bin Shumayl informed us; Abd al-Jalil bin Atiyyah narrated to him, and he transmitted this report from Abu Mijlaz.