Well, the Hijri date 14 Rabi Al Thani 1391 corresponds to the Gregorian date Monday, 7 June 1971. This date lies in the fourth month of the Hijri year 1391 AH, which is Rabi Al-Thani of 1391 AH. Both this Hijri and Gregorian date occur on the single day that is Monday without any doubt. The Arabic date 1391/04/14 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 7 June 1971 to its equivalent Arabic date.
The following is the conversion of the Arabic date 14 Rabi Al Thani 1391 AH to its equivalent Gregorian date.
قُلْ أَرَءَيْتُم مَّا تَدْعُونَ مِن دُونِ ٱللَّهِ أَرُونِى مَاذَا خَلَقُوا۟ مِنَ ٱلْأَرْضِ أَمْ لَهُمْ شِرْكٌۭ فِى ٱلسَّمَٰوَٰتِ ۖ ٱئْتُونِى بِكِتَٰبٍۢ مِّن قَبْلِ هَٰذَآ أَوْ أَثَٰرَةٍۢ مِّنْ عِلْمٍ إِن كُنتُمْ صَٰدِقِينَ
Say (unto them, O Muhammad): Have ye thought on all that ye invoke beside Allah? Show me what they have created of the earth. Or have they any portion in the heavens? Bring me a scripture before this (Scripture), or some vestige of knowledge (in support of what ye say), if ye are truthful.
Surah Al-Ahqaf(46:4)