Well, the Hijri date 18 Rajab 1439 corresponds to the Gregorian date Wednesday, 4 April 2018. This date lies in the seventh month of the Hijri year 1439 AH, which is Rajab of 1439 AH. Both this Hijri and Gregorian date occur on the single day that is Wednesday without any doubt. The Arabic date 1439/07/18 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 April 2018 to its equivalent Arabic date.
The following is the conversion of the Arabic date 18 Rajab 1439 AH to its equivalent Gregorian date.
وَوَصَّيْنَا ٱلْإِنسَٰنَ بِوَٰلِدَيْهِ حُسْنًۭا ۖ وَإِن جَٰهَدَاكَ لِتُشْرِكَ بِى مَا لَيْسَ لَكَ بِهِۦ عِلْمٌۭ فَلَا تُطِعْهُمَآ ۚ إِلَىَّ مَرْجِعُكُمْ فَأُنَبِّئُكُم بِمَا كُنتُمْ تَعْمَلُونَ
We have enjoined on man kindness to parents; but if they strive to make thee join with Me that of which thou hast no knowledge, then obey them not. Unto Me is your return and I shall tell you what ye used to do.
Surah Al-Ankaboot(29:8)
Sahih al-Bukhari
Prophetic Commentary on the Qur'an (Tafseer of the Prophet (pbuh))
The Statement of Allah ta'ala: "And [He has sent him (Prophet Muḥammad pbuh) also to] others among them (Muslims) who have not yet joined them..." (V.62:3)
Narrated Abu Huraira:
While we were sitting with the Prophet (ﷺ) Surat Al-Jumu'a was revealed to him, and when the Verse, "And He (Allah) has sent him (Muhammad) also to other (Muslims).....' (62.3) was recited by the Prophet, I said, "Who are they, O Allah's Messenger (ﷺ)?" The Prophet (ﷺ) did not reply till I repeated my question thrice. At that time, Salman Al-Farisi was with us. So Allah's Messenger (ﷺ) put his hand on Salman, saying, "If Faith were at (the place of) Ath-Thuraiya (pleiades, the highest star), even then (some men or man from these people (i.e. Salman's folk) would attain it."
Sahih al-Bukhari 4897