بسم الله الرحمن الرحيم
والصلوة والسلام على رسوله الكريم
When the imam makes the taslim, saying “as-Salamu alaykum wa-Rahmatullah” first to the right and then to the left, it is from the sunna to make the taslim concurrently with the imam. It is observed that a large number of Muslim worshipers commit an error in waiting for the imam to conclude the taslim to the right and to the left before they offer the taslim themselves. The Hadith of Itban b. Malik al-Ansari رضى الله عنه in which the Prophet صلى الله عليه وآله وسلم led the Salat in his house, is a proof that the followers are to make the taslim concurrently with the imam:
فَقَامَ فَصَفَفْنَا خَلْفَهُ ثُمَّ سَلَّمَ، وَسَلَّمْنَا حِينَ سَلَّمَ
“He (Prophet) stood (for Salat) and we arranged in rows behind him. Then he made the taslim and we made the taslim when he made taslim.”
Therefore, when the imam makes the taslim first the right, all those praying behind him should likewise make the taslim turning their faces to the right. They should not wait until the imam has made the taslim to the right and left before commencing with the taslim to the right.