﴿ ۞ 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 ﴾

“THEY WILL ASK thee about the new moons. Say: "They indicate the periods for [various doings of] mankind, including the pilgrimage." However, piety does not consist in your entering houses from the rear, [as it were,] but truly pious is he who is conscious of God. Hence, enter houses through their doors, and remain conscious of God, so that you might attain to a happy state.”

The waxing and waning of the moon are meant to serve only as measures of time. The superstitious believe that the days when the moon is waxing are auspicious while the days of the moon’s waning are inauspicious. The moon, in fact, is an almanac of nature appearing in the sky so that people may plan the timings of their worldly affairs as well as their worship. But there are many people who have come to regard mere outward observance as religiosity.