It is narrated from Jabir (may Allah be pleased with him) that the Prophet (peace and blessings of Allah be upon him) said: "None of you should lie on his back and place one foot over the other." Narrated by Muslim.
Hadith Referenceمشكوة المصابيح / كتاب الآداب / 4710
Hadith Gradingالألبانی:صَحِيح | زبیر علی زئی:صحيح
Hadith Takhrij´تحقيق و تخريج: محدث العصر حافظ زبير على زئي رحمه الله` «رواه مسلم (2099/74)»