Well, the Hijri date 21 Rabi Al Thani 1399 corresponds to the Gregorian date Monday, 19 March 1979. This date lies in the fourth month of the Hijri year 1399 AH, which is Rabi Al-Thani of 1399 AH. Both this Hijri and Gregorian date occur on the single day that is Monday without any doubt. The Arabic date 1399/04/21 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 19 March 1979 to its equivalent Arabic date.
The following is the conversion of the Arabic date 21 Rabi Al Thani 1399 AH to its equivalent Gregorian date.
وَإِنَّ يُونُسَ لَمِنَ ٱلْمُرْسَلِينَ
And lo! Jonah verily was of those sent (to warn)
Surah As-Saaffaat(37:139)
Sahih al-Bukhari
One-fifth of Booty to the Cause of Allah (Khumus)
Chapter: The houses of the wives of the Prophet saws
Narrated `Aisha:
(the wife of the Prophet) When the sickness of Allah's Messenger (ﷺ) got aggravated, he asked the permission of his wives that he should be treated in my house, and they permitted him.
Sahih al-Bukhari 3099
