Praying immediately to the right or left of the imaam when crowded
Question: If the congregation became crowded in the masjid, then is it permissible for some of them to pray (immediately) to the right of the imaam and his left. And is the one who prays (immediately) to the right of the imaam regarded as having attained the reward for praying in the first row?
Response: If the congregation became crowded in the masjid, then there is no harm in praying (immediately) to the right of the imaam or to his left, or to the right of him only, and those who do so are not regarded as (being in) the first row, because the first row is the first row behind theimaam.
Shaykh Ibn ‘Uthaymeen
Majmoo’ Fataawa wa Rasaa.il Muhammad ibn Saalih al-‘Uthaymeen – Volume 13, Fatwa No.418 source:fatwaonline.com