Sahih Muslim
The Book of Commentary (Kitab Al-Tafsir)
Book Number: 041 / Hadith Number: 7177
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).