Walimah is the food which is made for a pleasant event, especially the wedding ceremony.
Its time: At concluding the wedding contract, after the wedding night, or at the wedding night. It is better to set up the Walimah after the wedding night because the Prophet (peace be upon him) did not set up a Walimah but after the conclusion of marriage. (1)
Its amount: A Walimah is sufficient by any kind of food, moreover it is not a condition to slaughter an animal because it was reported on the authority of Anas that he said: "The Prophet (peace be upon him) stayed for three rights between Khaybar and Medina and was married to Safiyah. I invited Muslims to his wedding banquet and there was neither meat nor bread in that banquet but the Prophet (peace be upon him) ordered Bilal to spread the leather mats on which dates, dried yogurt and butter were put." (2)
The ruling on answering the Walimah invitation: It is obligatory to answer the invitation of the Walimah except if there is an excuse or a deniable act which a person cannot change or forbid (3) because of the Hadith of "When you are invited to a wedding banquet, you must go to it." (4)
An-Nithar: is to give away food, money, or clothes; all these actions are reprehensible. If the gifts which the groom's family offer are food, it is reprehensible for two reasons:
The first is: It is a scorn for the bounty.
The second is: It expresses lowness and against chivalry.
If the gifts are money, it is reprehensible because it is a wasting of money.
Moreover, it is reprehensible to pick up An-Nithar because it is against chivalry. (5)
(1) See, I`anat At-Talibin 3/357 and Al Majmu` Sharh Al Muhadhdhab 16/390.
(2) Reported by Al Bukhari in the chapter on the Battle of Khaybar, Hadith No. 3976 - 4/1543.
(3) See I`anat At-Talibin 3/358 and Al Majmu` Sharh Al Muhadhdhab 16/402.
(4) Reported by Al Bukhari in the chapter on the right of answering the wedding banquet, Hadith No. 4878 - 5/1984, and reported by Muslim in the chapter on the command of answering the invitation, Hadith No. 3584 - 4/152.
(5) See Al Majmu` Sharh Al Muhadhdhab 16/392, I`anat At-Talibin 3/369, and Ash-Sharh Al Mumti` 12/145.