Aboo Bakr bin Aboo Moosa al-Ash’aree reported: I heard my father saying in the presence of the enemy: The Messenger of Allaah (sallallaahu alayhi wa sallam) said,

“The gates of Jannah are under the shades of the swords.”
A man with a shaggy appearance got up and said,

“O Aboo Moosa! Did you hear the Messenger of Allaah (sallallaahu alayhi wa sallam) say that in person?”
Aboo Moosa replied in the affirmative; so he returned to his companions and said:

“I tender you farewell greetings.”
Then he broke the scabbard of his sword and threw it away. He rushed towards the enemy with his sword and fought with it till he was martyred.
[Muslim; found in Riyadhus-Saaliheen, the Book of Jihaad, number 1302]