Hadith: Arabic Text followed by English Translation.
عَنْ أَبِي بَكْرَةَ رَضِيَ اللَّهُ عَنْهُ عَنْ النَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ قَالَ
الزَّمَانُ قَدْ اسْتَدَارَ كَهَيْئَتِهِ يَوْمَ خَلَقَ اللَّهُ السَّمَوَاتِ وَالأَرْضَ السَّنَةُ اثْنَا عَشَرَ شَهْرًا مِنْهَا أَرْبَعَةٌ حُرُمٌ ثَلاثَةٌ مُتَوَالِيَاتٌ ذُو الْقَعْدَةِ وَذُو الْحِجَّةِ وَالْمُحَرَّمُ وَرَجَبُ مُضَرَ الَّذِي بَيْنَ جُمَادَى وَشَعْبَانَ
رواه البخاري ٣١٩٧
Abu Bakrah (may Allaah be pleased with him) that the Prophet (peace and blessings of Allaah be upon him) said:
The division of time has turned to its original form which was current the day Allaah created the heavens and earth. The year consists of twelve months of which four are sacred: three consecutive months, Dhu’l-Qa’dah, Dhu’l-Hijjah and Muharram, and Rajab of Mudar which comes between Jumada and Sha’baan.
Narrated by al-Bukhaari, 3197 .