Question:

There is usually a big dawat (dinner or lunch) at the home of the groom a day before the nikah. What is its ruling? How is it to take part in it?

Answer:

It is clear that a dawat (dinner or lunch) at the groom’s home, a day before the nikah, is not Sunnah. If this said dawat (dinner or lunch) is due to any custom or culture, then it being impermissible and an innovation (bid’ah) is also clear. There is also no permission to participate in it.

However, if the feeding of those guest who came from abroad was facilitated, and no custom was taken into consideration, then there is permission for that.

And Allah Ta’ala knows best.

(Hazrat Mufti) Ahmed Khanpuri (May Allah preserve him.)
Mahmoodul Fatawa Vol.3 Pg.289