It is narrated from Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "A man's prayer in congregation is superior by twenty-five prayers, each of them like the prayer he offers in his house."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 10062