Riyad as-Saliheen 1698
Buraidah (May Allah be pleased with him) said:
A man announced (the loss of his camel) in the mosque, uttering these words: "Has any one seen my red camel?" Upon this the Messenger of Allah ﷺ said, "May it not be restored to you! The mosques are built for what they are meant to be (i.e., prayer, remembrance of Allah, acquiring knowledge, etc.)."
[Muslim].
وعن بريدة رضي الله عنه أن رجلا نشد في المسجد فقال: من دعا إلى الجمل الأحمر، فقال رسول الله ﷺ : "لا وجدت، إنما بنيت المساجد لم بنيت له" ((رواه مسلم)).