Al-Kāfi

Hadith 1684
friday-prayer
3ـ جَمَاعَةٌ عَنْ أَحْمَدَ بْنِ مُحَمَّدٍ عَنِ الْحُسَيْنِ بْنِ سَعِيدٍ عَنْ فَضَالَةَ أَوْ عَنْ مُحَمَّدِ بْنِ سِنَانٍ عَنِ ابْنِ مُسْكَانَ عَنْ عَبْدِ الله بْنِ عَجْلاَنَ قَالَ قَالَ أَبُو جَعْفَرٍ (عَلَيْهِ الْسَّلام) إِذَا كُنْتَ شَاكّاً فِي الزَّوَالِ فَصَلِّ رَكْعَتَيْنِ فَإِذَا اسْتَيْقَنْتَ فَابْدَأْ بِالْفَرِيضَةِ.
3. A group has narrated from Ahmad ibn Muhammad from al-Husayn ibn Sa‘id from Fadalah or Muhammad ibn Sinan from ibn Muskan from ‘Abd Allah ibn ‘Ajalan who has said the following: “Abu Ja’far (a.s.), has said, ‘If you have doubts about Zawal (declining of the sun toward the west at noontime), perform two Rak‘at. When you become certain of Zawal, then begin performing obligatory Salah (prayer).”’
Source: Shaykh Muḥammad b. Yaʿqūb al-Kulaynī