Well, the Hijri date 20 Safar 1399 corresponds to the Gregorian date Thursday, 18 January 1979. This date lies in the second month of the Hijri year 1399 AH, which is Safar of 1399 AH. Both this Hijri and Gregorian date occur on the single day that is Thursday without any doubt. The Arabic date 1399/02/20 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 18 January 1979 to its equivalent Arabic date.
The following is the conversion of the Arabic date 20 Safar 1399 AH to its equivalent Gregorian date.
فَيَوْمَئِذٍۢ لَّا يُسْـَٔلُ عَن ذَنۢبِهِۦٓ إِنسٌۭ وَلَا جَآنٌّۭ
Surah Ar-Rahmaan(55:39)
Sahih al-Bukhari
Fasting
Chapter: To observe Saum (fast) or not during journeys
Narrated Ibn Abi `Aufa:
We were in the company of Allah's Messenger (ﷺ) on a journey. He said to a man, "Get down and mix Sawiq (powdered barley) with water for me." The man said, "The sun (has not set yet), O Allah's Messenger (ﷺ)." The Prophet (ﷺ) again said to him, "Get down and mix Sawiq with water for me." The man again said, "O Allah's Messenger (ﷺ)! The sun!" The Prophet (ﷺ) said to him (for the third time) "Get down and mix Sawiq with water for me." The man dismounted and mixed Sawiq with water for him. The Prophet (ﷺ) drank it and then beckoned with his hand (towards the East) and said, "When you see the night falling from this side, then a fasting person should break his fast."
Sahih al-Bukhari 1941