How do we know the current Friday is the Friday that the Prophet ﷺ observed? For example, could this have happened:

  • Muslims are observing Friday on a particular day since the Prophet's ﷺ time
  • Western colonizers find that the day they call Friday is actually Tuesday for the Muslims
  • Muslims are forced to adjust their calendar to have their Fridays align with the colonizers

I find it unlikely Europe was observing Friday on the same day as Muslims at the time of the Prophet ﷺ.

To clarify further, the world is following the Gregorian calendar. We use this for designating what the name of a day of the week is. How do we know we are following the same Friday as that of the Prophet's ﷺ?

More importantly, if we are not observing the correct Friday, will our Friday prayer be accepted?

  • This question is not about Islam and would be a better fit for history SE, where I even guess something similar was asked. What you say hardly makes sense Muslims had Jummah while others called it Friday, Vendredi, Freitag etc. when people of different cultures meet they don't adjust commonly known things but use both terms in parallel.
    – Medi1Saif
    Commented May 2, 2021 at 2:37
  • This question is not about the name of the day. How is it (or is it) possible that all cultures celebrate an entity called Friday on the same day, especially considering they have their own religion and calendar? Are we just following the Friday of the West? Commented May 2, 2021 at 2:45
  • Why should Muslims have a different day than Jumuah (same week day of the prophet) as their weekly day of gathering? This doesn't make sense at all. If they did so they shouldn't call themselves Muslims as they wouldn't follow Allah's order as stated in surat al-Jumuah nor his prophet-s sunnah.
    – Medi1Saif
    Commented May 2, 2021 at 2:55
  • 1
    I think what they’re asking is, during the time of the Prophet, he prayer Jummah using a different calendar than what the west adopted (i.e. the Gregorian calendar). The OP is confused because Muslims use the Gregorian calendar to adhere to the day of Jummah, not the way the Prophet did. So they’re unsure whether Muslims have been praying on the wrong day or not. (This is just my interpretation, I may be wrong). @user2233706 please let me know if I’m correct or not. Commented May 2, 2021 at 4:07
  • 1
    @user2233706 According to my research, people are saying that Fridays are the same on the Gregorian and Hijri calendar since the lengths of the days are the same. So there's no need to fret whether we're praying on a wrong day because it's been the same since the Prophet's time, the only difference is that we're using a different calendar. Even if that was the case about us praying on a wrong day as the Prophet, Allah says when it's Friday, go to the Masjid for Jummah. He didn't give certain criteria or what calendar to follow, he just said when it's Friday. Commented May 2, 2021 at 4:42

1 Answer 1


In the year of Hidjra, all regions of the whole Middle-East, including Arabia, as well as the Roman Empires already used a strict 7-days week. Long weeks to synchronise the week with the month, as it was practised earlier (known from the Babylonians) were no mor used. Jews, also present in Pre-Islamic Arabia, had their fixed week rythm that never run asynchronous although Jews spread out to Ethiopia and to Spain, and the Friday did not diverge from this counting at any time, either. Also calender changes (e.g. from Julian to Gregorian) never changed the rhythm of the week. It is thus very probable that the Friday prayer has indeed stayed in the same 7-day-rhythm since it has been established.

Moreover, it is related that

It was Friday from which Allah diverted those who were before us. For the Jews (the day set aside for prayer) was Sabt (Saturday), and for the Christians it was Sunday. And Allah turned towards us and guided us to Friday (as the day of prayer) for us.

Thus was the sequence when the Juma prayer was established, and it is still the same worldwide. No worldly power could have inserted days worldwide and over all religions without any notice or dispute.

  • That sounds reasonable. Do you have sources? Commented May 9, 2021 at 3:51
  • @user2233706 It is finally the absense of any sources or hints on a discrepency that makes it unlikely that anything has changed. See also judaism.stackexchange.com/questions/12868/…, contribution of Alex.
    – Jeschu
    Commented May 9, 2021 at 18:45

Not the answer you're looking for? Browse other questions tagged .