It was narrated 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: ‘Where are you from?’ They said: ‘From the inhabitants of ‘Iraq.’ He said: ‘Have you come with permission?’ They said: ‘Yes.’ Then they asked him about a man’s prayer in his house. ‘Umar said: ‘I asked the Messenger of Allah ﷺ and he said: “As for a man’s prayer in his house, it is light, so illuminate your houses.’””
Another chain with similar wording.

حَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا أَبُو الأَحْوَصِ، عَنْ طَارِقٍ، عَنْ عَاصِمِ بْنِ عَمْرٍو، قَالَ خَرَجَ نَفَرٌ مِنْ أَهْلِ الْعِرَاقِ إِلَى عُمَرَ فَلَمَّا قَدِمُوا عَلَيْهِ قَالَ لَهُمْ مِمَّنْ أَنْتُمْ قَالُوا مِنْ أَهْلِ الْعِرَاقِ . قَالَ فَبِإِذْنٍ جِئْتُمْ قَالُوا نَعَمْ . قَالَ فَسَأَلُوهُ عَنْ صَلاَةِ الرَّجُلِ فِي بَيْتِهِ . فَقَالَ عُمَرُ سَأَلْتُ رَسُولَ اللَّهِ ـ ﷺ ـ فَقَالَ " أَمَّا صَلاَةُ الرَّجُلِ فِي بَيْتِهِ فَنُورٌ فَنَوِّرُوا بُيُوتَكُمْ " . حَدَّثَنَا مُحَمَّدُ بْنُ أَبِي الْحُسَيْنِ، حَدَّثَنَا عَبْدُ اللَّهِ بْنُ جَعْفَرٍ، قَالَ حَدَّثَنَا عُبَيْدُ اللَّهِ بْنُ عَمْرٍو، عَنْ زَيْدِ بْنِ أَبِي أُنَيْسَةَ، عَنْ أَبِي إِسْحَاقَ، عَنْ عَاصِمِ بْنِ عَمْرٍو، عَنْ عُمَيْرٍ، مَوْلَى عُمَرَ بْنِ الْخَطَّابِ عَنْ عُمَرَ بْنِ الْخَطَّابِ، عَنِ النَّبِيِّ ـ ﷺ ـ نَحْوَهُ .