Q. If a person enters the Masjid and the Salaah has started, should he join the rows of Salaah from the right or the left?
A. It is Sunnah for the Imaam to stand in the center of the rows in Salaah. Hence, the rows in Salaah should be equally aligned on either side of the Imaam.
If however, a person joins the Imaam in Salaah after the rows have been equally aligned on either side of the Imaam, then a person should join the Imaam in Salaah from the right side; but if the rows have not been equally aligned on the left side of the Imaam, then a person should join the Imaam in Salaah from the left side. (Shaami 1/568)
Allah Ta’ala Knows Best
Mufti Ismaeel Bassa
This answer was collected from TheMufti.com, which is a fatwa portal managed by Mufti Ismaeel Bassa from South Africa.