It is narrated from Sayyiduna Abu Hurayrah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "When the gaze has entered (into the house), there is no longer any need to ask permission."
Imam al-Tabarani (may Allah have mercy on him) said: "No one narrated this hadith from Kathir (may Allah have mercy on him) except al-Walid (may Allah have mercy on him), and his son is alone in narrating it from him."
Hadith Referenceالمعجم الأوسط / باب الألف / 1372
Hadith Takhrij«أخرجه أبو داود فى «سننه» برقم: 5173، والبيهقي فى «السنن الكبرى» برقم: 17737، وأحمد فى «مسنده» برقم: 8908، والبزار فى «مسنده» برقم: 8122، 8121»