Al-Kāfi - The Book of Prayer

Chapter: Performing Salah (Prayer) In One Piece of Cloth, How Much clothing a woman Needs, Salah (prayer) of Naked People and Putting One’s Clothes in a Certain Manner, Garb with a Sash 10ـ وَعَنْهُ عَنْ ٠َدَ بْنِ الْحَسَنِ بْنِ عَلِيٍّ عَنْ عَ٠ْرِو بْنِ سَعِيدٍ عَنْ ٠ُصَدِّقِ بْنِ صَدَقَةَ عَنْ عَ٠َّارٍ السَّابَاطِيِّ عَنْ أَبِي عَبْدِ الله (عَلَيْهِ الْسَّلا٠) فِي الرَّجُلِ يُصَلِّي فَيُدْخِلُ يَدَيْهِ تَحْتَ ثَوْبِهِ قَالَ إِذَا كَانَ عَلَيْهِ ثَوْبٌ آخَرُ إِزَارٌ أَوْ سَرَاوِيلُ فَلاَ بَأْسَ وَإِنْ لَ٠ْ يَكُنْ فَلاَ يَجُوزُ لَهُ ذَلِكَ وَإِنْ أَدْخَلَ يَداً وَاحِدَةً وَلَ٠ْ يُدْخِلِ الأخْرَى فَلاَ بَأْسَ.

He (the Imam) said, ‘It is not an offense if he has other clothes on him, like a loincloth or pant (pajama); otherwise, it is not permissible, however, entering one hand is not harmful.’” وثق - Allamah Baqir al-Majlisi (Mirʾāt al-ʿUqūl fī Sharḥ Akhbār Āl al-Rasūl (5/304))