Question 463: When people finish offering congregational Salaah (Prayer), they say “May Allaah accept your Salaah.” “May Allaah accept ours and all Muslims’,” the other replies. What is your Fatwaa’ regarding this?
Answer: Saying “May Allaah accept your Salaah” to another who is sitting beside him after Tasleem (salutation of peace ending the Prayer) is not Mashroo` (Islaamically acceptable); rather, it is Bidd`ah (innovation in Islaam). The Prophet (peace be upon him) and the Companions (may Allaah be pleased with them) never did it. It was authentically reported that the Prophet (peace be upon him) stated: Anyone who introduces anything into this matter of ours (Islaam) that is not part of it will have it rejected.... read more here.