Well, the Hijri date 21 Rajab 1400 corresponds to the Gregorian date Wednesday, 4 June 1980. This date lies in the seventh month of the Hijri year 1400 AH, which is Rajab of 1400 AH. Both this Hijri and Gregorian date occur on the single day that is Wednesday without any doubt. The Arabic date 1400/07/21 is calculated using the Umm Al-Qura calendar and the sighting of the moon. One thing to remember is that this Arabic date may occur on different Gregorian date depending upon the region and country and obviously the moon.
If you are still not sure about the date then you can use our Arabic date converter.
The following is the conversion of the Gregorian date 4 June 1980 to its equivalent Arabic date.
The following is the conversion of the Arabic date 21 Rajab 1400 AH to its equivalent Gregorian date.
إِنَّ أَوَّلَ بَيْتٍۢ وُضِعَ لِلنَّاسِ لَلَّذِى بِبَكَّةَ مُبَارَكًۭا وَهُدًۭى لِّلْعَٰلَمِينَ
Lo! the first Sanctuary appointed for mankind was that at Becca, a blessed place, a guidance to the peoples;
Surah Aal-i-Imraan(3:96)
Sahih al-Bukhari
Merits of the Helpers in Madinah (Ansaar)
Chapter: The emigration of the Prophet (saws) to Al-Madina
Narrated Khabbab:
We migrated with Allah's Messenger (ﷺ) seeking Allah's Countenance, so our rewards became due and sure with Allah. Some of us passed away without eating anything of their rewards in this world. One of these was Mus`ab bin `Umar who was martyred on the day of the battle of Uhud. We did not find anything to shroud his body with except a striped cloak. When we covered his head with it, his feet remained uncovered, and when we covered his feet with it, his head remained uncovered. So Allah's Apostle ordered us to cover his head with it and put some Idhkhir (i.e. a kind of grass) over his feet. And there are some amongst us whose fruits have ripened and they are collecting them (i.e. they have received their rewards in this world).
Sahih al-Bukhari 3914
