Arabic coin ID

I would like a translation of the Arabic writing on this gold coin. It is 50 gram and believed to be from Saudi Arabia. Thank you.

Below the head:

الملك فهد بن عبد العزيز آل سعود

= "King Fahd bin 'Abdulaziz Al Sa'ud"

On top of the head:

خادم الحرمين الشريفين

= "Custodian/Guardian of the Two Holy Mosques"

On the reverse, the date ١٤٠٥ = 1984/5, and at the bottom:

توسعة الحرم النبوي الشريف

= "Expansion of the Prophet's Mosque"

Most difficult was the top legend on this side, because of the placement of the diacritics:

إِنَّمَا يَعْمُرُ مَسَاجِدَ اللَّهِ مَنْ آمَنَ بِاللَّهِ

= "But the mosques of Allah are built by those who believe in Allah" (can someone check this translation?)

This is a token, not a coin.

Thank you

The date is ٩ صفر (day 9th of the second month of the lunar based Islamic calendar)

In Gregorian calendar, that would be

Ah, thanks, I was not too sure what that meant.

And I forgot to say that ١٤٠٥ = 1405.