On the authority of Mu’aadh bin Jabal (radiAllaahu anhu) who said :
I said : O Messenger of Allaah, tell me of an act which will take me into Paradise and will keep me away from the Hell Fire.
He said : You have asked me about a great matter, yet it is easy for him for whom Allaah makes it easy : Worship Allaah, without associating any partners with Him; establish the Prayer; pay the Zakaah; fast in Ramadaan; and make the Pilgrimage to the House.
Then he said : Shall I not guide you towards the Means of Goodness ? Fasting is a shield; charity wipes away sin as water extinguishes fire; and the Praying of a man in the depths of the Night. Then he recited : [Those] who forsake their beds, to invoke their Lord in fear and hope, and they spend (charity in Allaah’s Cause) out of what We have bestowed on them. No person knows what is kept hidden for them of joy as a reward for what they used to do. [Soorah as-Sajdah, 16-17]
Then he said : Shall I not inform you of the head of the matter, its pillar and its peak ?
I said : Yes, O Messenger of Allaah.
He said : The head of the matter is Islaam, its pillar is the Prayer and its peak is jihaad.
Then he said : Shall I not tell you of the foundation of all of that ?
I said : Yes, O Mesenger of Allaah.
So he took hold of his tongue and said : Restrain this.
I said : O Prophet of Allaah, will we be taken to account for what we say with it ?
He said : May your mother be bereaved of you, O Mu’aadh ! Is there anything that throws people into the Hell Fire upon their faces - or : on their noses - except the harvests of their tongues ?
It was related by at-Tirmidhee, who said it was a good and sound hadeeth.
excerpt from 40 hadiths of imam An-Nawawi