(29) Excellent Qualities and Description of the Prophet
كتاب الفضائل والشمائل
(5a) Chapter: The Signs of Prophecy - Section 1
(5) باب علامات النبوة - الفصل الأول
Mishkat al-Masabih 5854 
Anas said that when the people of Mecca asked God's messenger to show them a sign, he showed them the moon in two pieces between which they were able to see Hira. (Bukhari and Muslim.)
وَعَن أنسٍ قَالَ: إِنَّ أَهْلَ مَكَّةَ سَأَلُوا رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ أَنْ يُرِيَهُمْ آيَةً فَأَرَاهُمُ الْقَمَرَ شِقَّتَيْنِ حَتَّى رَأَوْا حِرَاءً بَيْنَهُمَا. مُتَّفق عَلَيْهِ
 مُتَّفق عَلَيْهِ  (الألباني)حكم :
Reference : Mishkat al-Masabih 5854
In-book reference : Book 29, Hadith 112