Well, the Hijri date 26 Rajab 1400 corresponds to the Gregorian date Monday, 9 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 Monday without any doubt. The Arabic date 1400/07/26 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 9 June 1980 to its equivalent Arabic date.
The following is the conversion of the Arabic date 26 Rajab 1400 AH to its equivalent Gregorian date.
وَكَذَٰلِكَ زَيَّنَ لِكَثِيرٍۢ مِّنَ ٱلْمُشْرِكِينَ قَتْلَ أَوْلَٰدِهِمْ شُرَكَآؤُهُمْ لِيُرْدُوهُمْ وَلِيَلْبِسُوا۟ عَلَيْهِمْ دِينَهُمْ ۖ وَلَوْ شَآءَ ٱللَّهُ مَا فَعَلُوهُ ۖ فَذَرْهُمْ وَمَا يَفْتَرُونَ
Thus have their (so-called) partners (of Allah) made the killing of their children to seem fair unto many of the idolaters, that they may ruin them and make their faith obscure for them. Had Allah willed (it otherwise), they had not done so. So leave them alone with their devices.
Surah Al-An'aam(6:137)