Is there any harm in thirty or fifty people gathering for the conclusion of a marriage contract?
There is no harm if the said number or more or less attends, as this is a means of announcing the marriage, which is required by Shari`ah (Islamic law). It is confirmed that the Prophet (peace be upon him) said,
"Announce the contract of marriage."
The obligation is that two upright witnesses are present at the time of concluding the marriage contract along with the Waliy (a legally accountable person acting for a woman regarding marriage) and the bridegroom. May Allah grant us success. May peace and blessings be upon our Prophet, his family, and Companions.