Bara' reported: When the Ansar performed the Pilgrimage, they did not enter their houses but from behind. A person from the Ansar came and he began to enter from his door but it was said to him (why he was doing something in contravention to the common practice of coming to the houses from behind). Then this verse was revealed." Piety is not that you come to the doors from behind" (ii. 189).
Source: sunnah.com
Other translations
Arabic
حَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا غُنْدَرٌ، عَنْ شُعْبَةَ، ح وَحَدَّثَنَا مُحَمَّدُ بْنُ الْمُثَنَّى، وَابْنُ بَشَّارٍ - وَاللَّفْظُ لاِبْنِ الْمُثَنَّى - قَالاَ حَدَّثَنَا مُحَمَّدُ بْنُ جَعْفَرٍ، عَنْ شُعْبَةَ، عَنْ أَبِي إِسْحَاقَ، قَالَ سَمِعْتُ الْبَرَاءَ، يَقُولُ كَانَتِ الأَنْصَارُ إِذَا حَجُّوا فَرَجَعُوا لَمْ يَدْخُلُوا الْبُيُوتَ إِلاَّ مِنْ ظُهُورِهَا - قَالَ - فَجَاءَ رَجُلٌ مِنَ الأَنْصَارِ فَدَخَلَ مِنْ بَابِهِ فَقِيلَ لَهُ فِي ذَلِكَ فَنَزَلَتْ هَذِهِ الآيَةُ {وَلَيْسَ الْبِرُّ بِأَنْ تَأْتُوا الْبُيُوتَ مِنْ ظُهُورِهَا} .
sunnah.com