“Baarakallah” or “No thank you”
We go to someone’s house and find them eating food. Normally, they ask us to join them. If we do not want to eat what should we say? Some people say ‘Baarakallah’ while others say ‘No thank you’.
We understand from Hadeeth that if the one who is invited does not want to participate he should make du’aa of barakah (blessing)for the one who has invited him. He should say, ‘Baarakallahu Lanaa wa La Kum’. (May Allah give the Barakah to you and us).[Riyaadhul Jannah-volume 2, page 12, question 4]