Mu'jam Kabir Tabarani 17336 — from Sayyiduna Mu'adh bin Jabal that he

Shahr bin Hawshab (may Allah have mercy on him) narrates from Sayyiduna Mu'adh bin Jabal (may Allah be pleased with him) that he said: O Messenger of Allah! Tell me of a deed that will admit the one who does it into Paradise. He (peace and blessings be upon him) said: "Bakhin bakhin (excellent, excellent)! You have asked about something great, yet it is easy for the one for whom Allah makes it easy: that you worship Allah and associate nothing with Him, establish the obligatory prayer, pay the obligatory zakah, fast Ramadan, and perform Hajj to the House. And I will also tell you the head of this matter, its pillar and the peak of its hump: the head of this matter is bearing witness that there is no god worthy of worship but Allah, and its pillar and the peak of its hump is jihad. And I will also tell you the doors of goodness: fasting is a shield, charity extinguishes sin just as water extinguishes fire, and the servant's standing (in prayer) at night (is also a door of goodness)." And the Messenger of Allah (peace and blessings be upon him) recited this verse: "Their sides forsake their beds" [Al-Sajdah: 16]. Then he said: "And I will also tell you of what has more control than all of that." And he moved his mount on, and I drew near to the people, then drew near to him and said: O Messenger of Allah! What is it that has more control over all of that? He (peace and blessings be upon him) pointed with his hand to his tongue. I said: The tongue? As though I considered it trivial. He (peace and blessings be upon him) said: "May your mother be bereaved of you, O Mu'adh bin Jabal! Does anything throw people into the fire of Hell except the harvests of their tongues?"