Dought & clear, - Why is the week seven days?.

If Allah swt made everything in 6 days why do we have 7 days in a week?.
Praise be to Allaah.
Firstly:
We cannot be certain about anything with regard of the division of the
week into seven days, or the time when this division began – was it
before the creation of the heavens and the earth, or was the creation
of the heavens and the earth what led to this division? The reason for
that is that we have no clear evidence which states anything certain
to that effect. But what is indicated by a study of calendars and the
customs and reports of different nations is that the division of the
week into seven days is connected to religion and taken from it, and
that it has to do with reports and rulings of religion.
Shaykh al-Islam Ibn Taymiyah (may Allaah have mercy on him) said
inMajmoo' al-Fataawa(7/95):
Every nation that does not have a Book has no names for days of the
week in their languages, rather they have names for the day, the month
and the year, because that may be known on tangible and rational ways,
so the nations gave them names, because expression follows
visualization. But the week was only known by hearing (reports). It
was not known that Allaah created the heavens and the earth and
everything in between in six days then rose over the Throne except by
the words of the Prophets who were enjoined to gather together on one
day of the week to worship Allaah and remember the first week in which
Allaah began to create the universe. In Arabic and Hebrew and the
languages of those who learned from them, there are words for the days
of the week, unlike the language of the Turks and others like them;
there are no words for the days of the week in their language because
they did not know of that so they have no words for it.
Dr. Jawaad 'Ali says:
The month is divided into four sections, and each section is a week
composed of seven days.
The idea of this division is attributed to the Babylonians, but the
days of the week and their order in the manner that is known until now
is a system that appeared long after them. The week (shavu'ah in
Hebrew) is mentioned in the Torah, in the Book of Genesis. Based on
both the Jewish Sabbath and the story of creation, the week was
organized along the lines that are still prevalent today. End quote.
Al-Mufassal fi Tareekh al-'Arab qabl al-Islam(16/96).
And Allaah knows best.