Hadith: The Hour will not appear until people boast about mosques

عن أنس رضي الله عنه قال: قال رسول الله صلى الله عليه وسلم : «لا تقوم السَّاعة حتى يَتَبَاهَى النَّاس في المسَاجد».
[صحيح] - [رواه أبو داود]

Anas (may Allah be pleased with him) reported that the messenger of Allah (may Allah's peace and blessings be upon him) said: "The Hour will not appear until people boast about mosques."
Sahih/Authentic. - [Abu Dawood]

Explanation

This Hadīth means that the Hour will not appear until people boast about mosques: their beautiful architecture, decoration, embellishment, height, and tall walls, so that some would say: "Our mosque is better than the mosque of the other neighborhood," and so on. Boasting is induced by actions, which involve an exaggerated decoration of mosques, building them to considerable heights, etc., so that they appear more splendid than other mosques. As such, it is mandatory to avoid excessiveness in building and decorating mosques, because mosques are not built for such ends. They are built only to be maintained with prayer, remembering and obeying Allah, the Almighty. In this respect, Allah says: {The mosques of Allah shall be maintained only by those who believe in Allah and the Last Day and establish the prayer.} [Sūrat At-Tawbah: 18] ‘Umar (may Allah be pleased with him) ordered building a mosque and gave these instructions: "[Build only to] shelter people from rain. Do not paint red or yellow, lest you should distract people's attention." Here, ‘Umar instructs to build a mosque that will protect people from rain and heat when they pray in it. Decoration is not advised. Anas said: "They will boast about [mosques], but little will they maintain them." Ibn ‘Abbās said: "Indeed you will embellish [mosques] just as the Jews and Christians embellished [their churches and synagogues]." To conclude, boasting about mosques is one of the signs of the Hour which will appear only when religious observance has grown weak. People will not be doing things for the sake of Allah, the Almighty, but for ostentation, reputation, competition, and boasting.