What does Islam say about:
- Building huge mosques.
- Building overly tall minarets.
- Extravagantly adorning and decorating mosques.
- Decorating mosques with valuable metals or jewels.
What does Islam say about:
On building mosques
Building mosques is among the best deeds one may do:
In one narration an-Nasa-I and ibn Majah added
"Whoever builds a Masjid in which Allah is remembered, ..."
In another ibn Majah added:
'Whoever builds a mosque for the sake of Allah (from his own wealth) ...
Another version of this hadith in sunan ibn Majah says:
"Whoever builds a mosque for the sake of Allah, like a sparrow's nest for Allah or even smaller, Allah will build for him a house in Paradise."
These ahadith show the importance of building a mosque and also what is necessary for the acceptance for that beside this one may read in the Qur'an another condition:
And [there are] those [hypocrites] who took for themselves a mosque for causing harm and disbelief and division among the believers and as a station for whoever had warred against Allah and His Messenger before. And they will surely swear, "We intended only the best." And Allah testifies that indeed they are liars. (107)
Do not stand [for prayer] within it - ever. A mosque founded on righteousness from the first day is more worthy for you to stand in. Within it are men who love to purify themselves; and Allah loves those who purify themselves. (9:107-108)
How the first mosque look alike?
In the lifetime of Allah's Messenger (ﷺ) the mosque was built of adobes, its roof of the leaves of date-palms and its pillars of the stems of date-palms. Abu Bakr did not alter it. 'Umar expanded it on the same pattern as it was in the lifetime of Allah's Messenger (ﷺ) by using adobes, leaves of date-palms and changing the pillars into wooden ones. 'Uthman changed it by expanding it to a great extent and built its walls with engraved stones and lime and made its pillars of engraved stones and its roof of teak wood. (Sahih al-Bukhari and sunan abi Dawod)
It was anything but extravagant it hardly looked like any mosque now!
Allah the Almighty says:
O children of Adam, take your adornment at every masjid, and eat and drink, but be not excessive. Indeed, He likes not those who commit excess. (7:31)
Even if we are recommended to wear our best clothes when visiting a mosque we are asked not to be excessive as is the general ruling in Islam:
And [they are] those who, when they spend, do so not excessively or sparingly but are ever, between that, [justly] moderate (25:67)
Therefore the prophet () said:
In his introduction to the hadith describing the first mosque and the expandation during the lifetime of 'Omar ibn al-Khattab in his sahih imam al-Bukhari also quoted the following statements:
'Umar ordered that the mosque be rebuilt and he said: Protect the people from rain, but beware of using red or yellow (for adornment) and distracting the people.
Anas said: They build mosques about boast about that, but they do not use them for worship except rarely.
Ibn 'Abbaas said: You are going to adorn (mosques) as the Jews and Christians adorn (their places of worship). (Source of the translation: islamqa #)11
(See also in sunan abi Dawod)
These statements should show that extravagance is not the goal of building a mosque a mosque in first place is a place of worship anything (any extravagance) that might disturb you during your prayer is frowned upon (or even haram) in a mosque (based on ahadith such as here in sahih al-Bukhari).