Sunan al-Tirmidhī · Musnad Aḥmad

Mu‘ādh ibn Jabal (may Allah be pleased with him) reported: I was on a journey in the company of the Prophet (may Allah's peace and blessings be upon him). One morning I was close to him when we were on the move, so I said: O Messenger of Allah, inform me of a deed that admits me to Paradise and keeps me far from Hellfire. He said: "You have asked me about a great matter, which is, indeed, easy for whomever Allah makes it easy.

Worship Allah and do not associate anything with Him, establish the prayer, give Zakah, fast Ramadan, and make Hajj to the House." Then he said: "Shall I not guide you to the gates of goodness?

Fasting is a shield, charity extinguishes sin as water extinguishes fire, and a man's prayer in the dead of night." He said: Then he recited: "{They forsake their beds} until he reached {what they used to do} [Surat as-Sajdah:  16-17]." Then he said: "Shall I inform you of the head of the whole matter, its pillar, and its peak?" I said: Yes, O Messenger of Allah.

He said: "The head of the matter is Islam, its pillar is the prayer, and its peak is Jihad." Then he said: "Shall I inform you of what holds all these things?" I said: Yes, O Prophet of Allah. So he took hold of his tongue and said: "Keep this under control." I said: O Prophet of Allah, are we held accountable for what we speak? He said: "May your mother lose you, O Mu‘ādh! What else casts people into Hellfire on their faces or on their noses other than the harvest of their tongues?"