Is it permissible for a group of people to gather weekly to perform Dhikr or seek forgiveness for a specific period, and likewise to seclude themselves (i'tikaf) in one of their homes for two or three days, fasting and performing night prayers, then questioning each other about dreams and their interpretations, justifying this by its being narrated from the Messenger of Allah (peace be upon him)?

Specifying Dhikr to certain minutes as an act of worship is an additional innovation (bid'ah). Organizing a weekly lesson is permissible, and I'tikaf (spiritual retreat) is only valid in a mosque. Performing Qiyam al-Layl (night prayer) in congregation is permissible, unless a specific night is designated for it. Specifying days for fasting that have not been specified is an innovation. Inquiring about dreams and their interpretation is legitimate.