Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) said: "Whoever would be pleased to meet Allah tomorrow as a Muslim, let him guard these prayers where the call (adhan) is made for them in congregation, for they are among the ways of guidance, and Allah, the Mighty and Majestic, has made these very ways of guidance obligatory for your Prophet (peace and blessings be upon him). And if you too were to pray in your houses as this one who stays behind prays in his house, you would abandon the Sunnah of your Prophet (peace and blessings be upon him), and if you abandon the Sunnah of your Prophet (peace and blessings be upon him), you will go astray. I saw a man being brought, supported between two men, until he was brought and made to stand in the row. And there came upon us a time when no one stayed away from the congregation except a hypocrite whose hypocrisy was known, and we used to walk with short, close steps."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 8566