سنن ابن ماجه

It was narrated that 'Abdullah said: "Whoever would like to meet Allah tomorrow (i.e. on the Day of Judgment) as a Muslim, let him preserve these five (daily) prayer when the call for them is given, for they are part of the ways of guidance, and Allah prescribed the ways of guidance to your Prophet. By Allah, if each of you prays in his house, you will have abandoned the Sunnah of your Prophet, and if you abandon the Sunnah of your Prophet you will go astray. I remember when no one stayed behind from the prayer except a hypocrite who was known for his hypocrisy. I have a man coming supported by two others, until he joined the row (of worshippers). There is no man who purifies himself and does it well, and comes to the mosque and prays there, but for every step that he takes, Allah raises him in status one degree thereby, and takes away one of his sins."