The invitation to a wedding feast and accepting it

Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) narrates that the Prophet (peace and blessings be upon him) said: "Accept the invitation of the one who invites, do not return a gift, and do not strike the Muslims."
Ahmad and al-Bazzar recorded it. In one narration of al-Bazzar the words are: "Accept the invitation of the one who invites when you are invited."
Al-Tabarani recorded it in al-Mu'jam al-Kabir; the narrators of Ahmad are the narrators of the Sahih.

Sayyiduna Abu Hurayrah (may Allah be pleased with him) said: The walimah is a right and a Sunnah. Whoever is invited to it and does not accept is guilty of disobeying Allah and His Messenger. As for khurs, i'dhar and takir, you have the choice (to go if you wish, and not to go if you wish). The narrator said: I said: By Allah! I do not know what khurs, i'dhar and takir mean. So he (that is, my teacher) told me: Khurs means the invitation for (a child's) birth, i'dhar means the invitation at the time of circumcision, and takir means that when a man builds a house, he invites people to it, prepares food and hosts them; regarding these, people have the choice: if they wish they may go, and if they wish they may not go. (Allamah al-Haythami says:) I say: Part of it is reported in the Sahih.
Al-Tabarani recorded it in al-Mu'jam al-Awsat; its chain contains a narrator, Yahya bin Uthman al-Taymi, whom Abu Hatim al-Razi and Ibn Hibban declared thiqah (trustworthy), while al-Bukhari (may Allah have mercy on him) and others declared him da'if (weak), and the rest of its narrators are the narrators of the Sahih.

Sayyiduna Abu Umamah (may Allah be pleased with him) narrates this saying of the Prophet (peace and blessings be upon him): "Whoever invites you, respond to him! (that is, accept the invitation)."
Al-Tabarani recorded it in al-Mu'jam al-Kabir; its chain contains a narrator, Muhammad bin Ubaydullah al-Arzami, and he is da'if (weak).

Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) narrates that the Prophet (peace and blessings be upon him) said: "When one of you is invited to food, he should go. If he is not fasting, he should eat, and if he is fasting, he should supplicate for blessing."
Al-Tabarani recorded it in al-Mu'jam al-Kabir, and its narrators are thiqat (trustworthy).

It is reported about Sayyiduna Ya'la bin Murrah (may Allah be pleased with him) that he was invited to a meal and sat down while he was fasting. The people began to eat, but he did not eat. It was said to him about this: By Allah! Had we known that you were fasting, we would not have invited you at all. Sayyiduna Ya'la (may Allah be pleased with him) said: Do not say that! For I heard the Prophet (peace and blessings be upon him) say: "Accept your brother's invitation, for you will gain one of two things through him: either there will be good there, in which case it is most deserving that you attend it, or it will be otherwise, in which case you will forbid him from it and command him to do good."
Al-Tabarani recorded it in al-Mu'jam al-Kabir; its chain contains a narrator, Umar bin Abdullah bin Ya'la, and he is da'if (weak).

Sayyiduna Abu Sa'id al-Khudri (may Allah be pleased with him) said that he prepared food for the Prophet (peace and blessings be upon him) and his Companions and invited them. When they came in, he set out the food. One of those present said: I am fasting. The Prophet (peace and blessings be upon him) said: "Your brother has invited you and gone to trouble for you, and you are saying, 'I am fasting'! Break your fast, and then, if you wish, fast a day in its place."
Al-Tabarani recorded it in al-Mu'jam al-Awsat; its chain contains a narrator, Hammad bin Abi Humayd, and he is da'if (weak), and the rest of its narrators are thiqat (trustworthy).

Qays bin Abi Hazim said: When someone is offered food or drink while he is fasting, he should say: I am fasting.
Al-Tabarani recorded it in al-Mu'jam al-Kabir, and its narrators are the narrators of the Sahih.

Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) said: If a man from the outlying areas (al-Awali) invited the Prophet (peace and blessings be upon him) at midnight to eat barley bread, he would accept his invitation.
Al-Tabarani recorded it in al-Mu'jam al-Saghir and al-Mu'jam al-Awsat; its chain contains a narrator, Abu Muslim, who used to lead al-A'mash about. Ibn Hibban declared him thiqah (trustworthy), saying: He makes mistakes. A group of scholars declared him da'if (weak).

Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) narrates that the Prophet (peace and blessings be upon him) said: "If I were invited to a trotter, I would accept."
Al-Tabarani recorded it in al-Mu'jam al-Awsat; its chain contains a narrator, Abdullah bin al-Mu'ammal, whom Ibn Sa'd and Ibn Hibban declared thiqah (trustworthy); he (Ibn Hibban) said: He makes mistakes. Two reports are transmitted from Ibn Hibban about this. A group of scholars declared this narrator da'if (weak).