من لا يحضره الفقيه, volume 1, page 390

Hadith.1152 - A man said to Imam Abu Ja'far (as), "I am the Imam of the mosque in our neighborhood, and when I bow (in ruku') with them, I hear the sound of their footsteps while I am in ruku'." Imam (as) replied: "Remain in your bowing position for as long as your bowing takes, and if they catch up, (continue); otherwise, stand up straight."

Translation: Bab Ul Qaim Publications·Thaqalayn link·The Arabic above is the original.

Hadith.1153 - Ishaq ibn Ammar narrated from Imam Jafar ibn Muhammad Al-Sadiq (as) that He said: "It is appropriate for the Imam's prayer to be suited to the ability of the weakest among those behind him."

Translation: Bab Ul Qaim Publications·Thaqalayn link·The Arabic above is the original.

Hadith.1154 - Mu'adh used to lead prayer in a mosque during the time of the Messenger of Allah (sw) and would make the recitation lengthy. One day, a man passed by while Mu'adh was reciting a long Surah, so the man recited (the prayer) for himself, completed it, and then rode off on his mount. When this incident reached The Prophet (sw), he sent for Mu'adh and said: "O’ Mu'adh, be careful not to be a source of hardship (fitnah). Recite from the shorter Surahs like 'By the sun and its brightness' (Ash-Shams) and similar ones."

Translation: Bab Ul Qaim Publications·Thaqalayn link·The Arabic above is the original.

Hadith.1155 - The Prophet (sw) was leading his companions in prayer one day when he heard the crying of a child, so he shortened the prayer.

Translation: Bab Ul Qaim Publications·Thaqalayn link·The Arabic above is the original.

Hadith.1156 – Zurarah and Muhammad ibn Muslim narrated from Imam Muhammad ibn Ali Al-Baqir (as) that He said: Amir al-Mu'minin (as) used to say: "Whoever recites (aloud) behind an Imam whom he follows (in prayer) and then dies will be resurrected on a different (incorrect) natural disposition (fitra)."

Translation: Bab Ul Qaim Publications·Thaqalayn link·The Arabic above is the original.