The Messenger of Allah ﷺ said, "A man's prayer in congregation is twenty-five times greater than his prayer performed alone."
حدثنا إسحق بن موسى الأنصاري حدثنا معن حدثنا مالك عن ابن شهاب عن سعيد بن المسيب
أن رسول الله ﷺ قال إن صلاة الرجل في الجماعة تزيد على صلاته وحده بخمسة وعشرين جزءا
Muslim also narrated it in Kitab al-Masajid, chapter on the merit of praying in congregation, etc., hadith no. 649, from the hadith of Malik through the same chain, and it is found in Muwatta 1/129 with different wordings conveying the same meaning. The hadith has several routes of transmission in Bukhari, Muslim, and others.