Surat Al-Baqara (The Cow) - البقرة

يَسْـَٔلُونَكَ عَنِ ٱلْأَهِلَّةِ قُلْ هِىَ مَوَٰقِيتُ لِلنَّاسِ وَٱلْحَجِّ وَلَيْسَ ٱلْبِرُّ بِأَن تَأْتُوا۟ ٱلْبُيُوتَ مِن ظُهُورِهَا وَلَٰكِنَّ ٱلْبِرَّ مَنِ ٱتَّقَىٰ وَأْتُوا۟ ٱلْبُيُوتَ مِنْ أَبْوَٰبِهَا وَٱتَّقُوا۟ ٱللَّهَ لَعَلَّكُمْ تُفْلِحُونَ ﴿١٨٩﴾

They ask you concerning the new moon. Say: They are times appointed for (the benefit of) men, and (for) the pilgrimage; and it is not righteousness that you should enter the houses at their backs, but righteousness is this that one should guard (against evil); and go into the houses by their doors and be careful (of your duty) to Allah, that you may be successful.