the following should be observed with regard to the wedding banquet:
first: it should be held ('aqb - fathul baaree: 9/242-244) three days after the first wedding night, since this is the tradition of the prophet which has reached us. on the authority of anas who said: "the prophet entered upon his wife and sent me to invite some men for food." [al-bukhaaree and al-baihaqi]. also on the authority of anas, he said: "the prophet married safiya, and her freedom was her dowry. he gave the feast for three days." [abu ya'laa and others: hasan].
second: one should invite the righteous to his banquet whether they be rich or poor. the prophet said: "do not be the friend of any except believers, and have only the pious eat your food." [abu dawood, at-tirmidhee and others: saheeh].
third: if one is able, he should have a feast of one or more sheep. based on the following hadith, anas said: "abdur-rahmaan came to al-madeenah, and the prophet assigned sa'ad ibn ar-rabee' al-ansaariy as his brother. sa'ad took him to his house, called for food, and they both ate. the sa'ad said: "o my brother, i am the wealthiest of the people of al-madeenah (in another version: "... of the ansaar"), so look to half of my property and take it (in another version: "... and i will divide my garden in half"). also, i have two wives (and you, my brother in allaah, have no wife), so look to which of mine pleases you more, so i can divorce her for you. then upon the completion of the prescribed waiting period, you may marry her." 'abdur-rahmaan said: "no, by allaah, may allah bless you in your family and your property. show me the way to the market-place."and so they showed him the way to the market-place and he went there. he bought and he sold and he made a profit. in the evening , he came back to the people of his house with some dried milk for cooking and some ghee. after that some time elapsed, until he appeared one day with traces of saffron on his garments. the prophet said to him: "what is this?" he said: "o messenger of allaah, i have married a woman among the ansaar." the prophet answered: "what did you give her for her dowry?" he answered: "the weight of five dirhams in gold." then, the prophet said: "may allaah bless you, give a feast if only with one sheep." 'abdur-rahmaan said: "i have seen myself in such a state that if i were to lift a stone, i would expect to find some gold or silver under it." anas said: "i saw after his death that each of his wives inherited one hundred thousand dinars." [al-bukhaaree, an-nasaa'ee and others].
also on the authority of anas he said: "i never saw the prophet sponsor such a wedding feast as the one he gave for zainab. he slaughtered a sheep and fed everyone meat and bread until they ate no more." [al-bukhaaree, muslim and others].