Surah Al-Baqarah, Ayah 189

They ask you, O Messenger, about the formation of the new moons and their changing states. Tell them in reply about the wisdom behind them: that they measure time for people, so that they know when to do their acts of worship, such as the months of Hajj and fasting, and the completion of the year for Zakat; they also fix the time frames of transactions, such as the deadlines for paying blood money or debts. It is not righteousness or goodness that you come to houses from the rear wearing your iḥrām for Hajj or Umrah, as they used to claim during the time of ignorance before Islam. Rather, true righteousness is the righteousness of whoever is mindful, outwardly and inwardly. So, enter houses from their correct doors, because it is easier for you and less troublesome. Allah does not overburden you with difficulty, so protect yourself from the punishment of Allah by doing good, in order that you may be successful in achieving what you wish for, and in escaping from what you fear.

They ask you (O Muhammad) about the crescents. Say: "These are signs to mark fixed periods of time for mankind and for the pilgrimage." It is not Al-Birr (piety, righteousness, etc.) that you enter the houses from the back, but Al-Birr is from Taqwa. So enter houses through their proper doors, and have Taqwa of Allah that you may be successful (189)

The Crescent Moons

Al-'Awfi related that Ibn 'Abbas said, "The people asked Allah's Messenger ﷺ about the crescent moons. Thereafter, this Ayah was revealed:

يَسْأَلُونَكَ عَنِ الْأَهِلَّةِ قُلْ هِيَ مَوَاقِيتُ لِلنَّاسِ

(They ask you (O Muhammad) about the crescents. Say, "These are signs to mark fixed periods of time for mankind...) so that they mark their acts of worship, the 'Iddah (the period of time a divorced woman or a widow is required to wait before remarrying) of their women and the time of their Hajj (pilgrimage to Makkah)." 'Abdur-Razzaq reported that Ibn 'Umar narrated that Allah's Messenger ﷺ said:

جَعَلَ اللهُ الْأَهِلَّةَ مَوَاقِيتَ لِلنَّاسِ، فَصُومُوا لِرُؤْيَتِهِ، وَأَفْطِرُوا لِرُؤْيَتِهِ، فَإِنْ غُمَّ عَلَيْكُمْ فَعُدُّوا ثَلَاثِينَ يَوْمًا

(Allah has made the crescents signs to mark fixed periods of time for mankind. Hence, fast on seeing it (the crescent for Ramadan) and break the fast on seeing it (the crescent for Shawwal). If it (the crescent) was obscure to you then count thirty days (mark that month as thirty days).)

This Hadith was also collected by Al-Hakim in his Mustadrak, and he said, "The chain is Sahih, and they (Al-Bukhari and Muslim) did not recorded it."

Righteousness comes from Taqwa

Allah said:

وَلَيْسَ الْبِرُّ بِأَن تَأْتُوا الْبُيُوتَ مِن ظُهُورِهَا وَلَٰكِنَّ الْبِرَّ مَنِ اتَّقَىٰ وَأْتُوا الْبُيُوتَ مِنْ أَبْوَابِهَا

(It is not Al-Birr (piety, righteousness, etc.) that you enter the houses from the back, but Al-Birr is from Taqwa. So enter houses through their proper doors.)

Al-Bukhari recorded that Al-Bara' said, "During the time of Jahiliyyah, they used to enter the house from the back upon assuming the Ihram. Thereafter, Allah revealed (the following Ayah):

وَلَيْسَ الْبِرُّ بِأَن تَأْتُوا الْبُيُوتَ مِن ظُهُورِهَا وَلَٰكِنَّ الْبِرَّ مَنِ اتَّقَىٰ وَأْتُوا الْبُيُوتَ مِنْ أَبْوَابِهَا

(It is not Al-Birr (piety, righteousness, etc.) that you enter the houses from the back but Al-Birr is from Taqwa. So enter houses through their proper doors.)

Abu Dawud At-Tayalisi recorded the same Hadith from Al-Bara' but with the wording; "The Ansar used to enter their houses from the back when returning from a journey. Thereafter, this Ayah (2:189 above) was revealed..."

Al-Hasan said, "When some people during the time of Jahiliyyah would leave home to travel, and then decide not to travel, they would not enter the house from its door. Rather, they would climb over the back wall. Allah the Exalted said:

وَلَيْسَ الْبِرُّ بِأَن تَأْتُوا الْبُيُوتَ مِن ظُهُورِهَا

(It is not Al-Birr (piety, righteousness) that you enter the houses from the back,)."

Allah's statement:

وَاتَّقُوا اللَّهَ لَعَلَّكُمْ تُفْلِحُونَ

(...and have Taqwa of Allah that you may be successful.) Have Taqwa of Allah, means to do what He has commanded you and refrain from what He has forbidden for you,

لَعَلَّكُمْ تُفْلِحُونَ

(that you may be successful.) tomorrow when you stand before Him and He thus rewards you perfectly.