Abu Wa'il narrates from Sayyiduna Abu Mas'ud, that is, Uqbah bin Amr (may Allah be pleased with him), that a man of the Ansar called Abu Shu'ayb noticed hunger in the face of the Messenger of Allah (peace and blessings be upon him). He said to his servant, who was a butcher: "Prepare food for us; perhaps I will invite the Messenger of Allah (peace and blessings be upon him) as one of five people." When the Messenger of Allah (peace and blessings be upon him) came, a man followed them without an invitation. The Messenger of Allah (peace and blessings be upon him) said to the host: "This man has followed us without an invitation; do you give him permission?" He gave permission.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصداق / 14543
Sayyiduna Jabir (may Allah be pleased with him) said: Abu Shu'ayb (may Allah be pleased with him) had a servant who was a butcher. When Abu Shu'ayb (may Allah be pleased with him) perceived that the Messenger of Allah (peace and blessings be upon him) and the Companions (may Allah be pleased with them) were hungry, he told his servant to send meat. Then he invited the Messenger of Allah (peace and blessings be upon him) to a meal as one of five people. When the Messenger of Allah (peace and blessings be upon him) came with his companions, five in all, a sixth man was with them. When he (peace and blessings be upon him) reached Abu Shu'ayb (may Allah be pleased with him), he said: "You invited five people, but this sixth man has come along with us. If you permit him, he will come in; otherwise he will go back." Abu Shu'ayb (may Allah be pleased with him) said: "I have given him permission; let him come in."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصداق / 14544
Abu Wa'il narrates likewise from Sayyiduna Abu Mas'ud (may Allah be pleased with him), from the Prophet (peace and blessings be upon him), and Imam Muslim (may Allah have mercy on him) recorded it from the hadith of Zuhayr bin Mu'awiyah.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصداق / 14545
Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) said that the Messenger of Allah (peace and blessings be upon him) said: "Whoever enters without an invitation enters as a raider and leaves as a thief."
(b) Al-Bahrani added to it: "The wedding feast (walimah) is a right; whoever does not accept the invitation to the walimah has disobeyed Allah and His Messenger."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصداق / 14546
Sayyidah Aishah (may Allah be pleased with her) said that the Messenger of Allah (peace and blessings be upon him) said: "Whoever goes to a people for food without having been invited enters as a sinner and eats what is not lawful for him."
No one narrated it from Rawh bin al-Qasim except Yahya bin Khalid, and he is majhul (unknown), one of Baqiyyah's shaykhs; Baqiyyah also has another chain for it that is majhul (unknown). The hadith of Ibn Umar (may Allah be pleased with them both) suffices.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصداق / 14547