Musannaf Ibn Abi Shaybah

Hazrat Abdullah bin Buraidah narrates from his father, who narrates from the Noble Prophet Muhammad (peace and blessings be upon him), that he (peace be upon him) forbade two types of clothing and two types of sitting. The two types of clothing are: that you pray in only a lower garment (pajama) and have nothing else on; and that a person prays in such a garment in which he does not display adornment. The two types of sitting are: that a person sits in such a way in one garment, tying his back and thighs, that his private parts become exposed; and that a person sits in both sunlight and shade.