Congregational Prayer and Its Virtue
Man Lā Yaḥḍuruh al-Faqīh|Volume 1|Book 1|Chapter 57
وَ سَأَلَهُ حَفْصُ بْنُ سَالِمٍ: إِذَا قَالَ اَلْمُؤَذِّنُ قَدْ قَامَتِ اَلصَّلاَةُ أَ يَقُومُ اَلنَّاسُ عَلَى أَرْجُلِهِمْ أَوْ يَجْلِسُونَ حَتَّى يَجِيءَ إِمَامُهُمْ قَالَ «لاَ بَلْ يَقُومُونَ عَلَى أَرْجُلِهِمْ فَإِنْ جَاءَ إِمَامُهُمْ وَ إِلاَّ فَلْيُؤْخَذْ بِيَدِ رَجُلٍ مِنَ اَلْقَوْمِ فَيُقَدَّمَ.
Hafs ibn Salim asked: "When the muezzin (caller to prayer) says 'The prayer has been established' (during the iqamah), should the people stand up or remain seated until their Imam arrives?" He عليه السلام replied: "No, they should stand up. If their Imam arrives, they proceed with him; otherwise, a man from among the congregation should be taken by the hand and brought forward to lead."
- Ṣaḥīḥ al-Faqīh, p. 54