It wasnarrated that 'Asim bin 'Amr said:
"A group from the people of'Iraq came to 'Umar and when they came to him, he said to them:'Whereare you from?' They said: 'From the inhabitants of'Iraq.' He said:'Have you come with permission?' They said:'Yes.' Then they asked himabout a man's prayer in his house.'Umar said: 'I asked the Messengerof Allah (ﷺ) and he said:"As for a man's prayer in his house, it islight, so illuminateyour houses.'""Another chain with similar wording. (FR)
English reference (FR): Vol. 1, Book 5, Hadith 1375 (FR)
Arabic reference (FR): Book 5, Hadith 1437 (FR)