On the authority of Anas radhiyallahu 'anhu, the Prophet ﷺ said:

((لاَ تَقُومُ السَّاعَةُ حَتَّى يَتَبَاهَى النَّاسُ فِى الْمَسَاجِدِ)) “The Hour will not be established until people show off with regards to [decorating] the masjids.” [Reported by Abu Dawud (449) - graded Saheeh by Sheikh Albani in Saheeh Abi Dawud]