Al-Kāfi

Hadith 1536
dress-adornmentprayer-etiquette
5ـ عَلِيُّ بْنُ مُحَمَّدٍ رَفَعَهُ عَنْ أَبِي عَبْدِ الله (عَلَيْهِ الْسَّلام) فِي رَجُلٍ يُصَلِّي فِي سَرَاوِيلَ لَيْسَ مَعَهُ غَيْرُهُ قَالَ يَجْعَلُ التِّكَّةَ عَلَى عَاتِقِهِ.
5. Ali ibn Muhammad in a marfu‘ manner has narrated the following: “About a man who performs Salah (prayer) wearing a pant (pajama) with no other clothes, abu ‘Abd Allah (a.s.), has said, ‘He is to secure it with a drawstring to his shoulder.’”
Source: Shaykh Muḥammad b. Yaʿqūb al-Kulaynī