Today's Hadith

Prophet (صلى الله عليه و سلم) said Ameen thrice when Jibreel came and said..

Kaab Ibn Ujrah ( رضي الله عنه) relates that Rasulullah (صلى الله عليه و سلم) said :Come near to the mimbar and we came near the mimbar. When He (صلى الله عليه و سلم ) climbed the first step of the mimbar, He (صلى الله عليه و سلم) said "Aameen", When He (صلى الله عليه و سلم ) ascended the second step, He ( صلى الله عليه و سلم) said "Aameen", When He (صلى الله عليه و سلم ) climbed the third step, He (صلى الله عليه و سلم ) said "Aameen" When He ( صلى الله عليه و سلم) came down, We said "O Rasool of Allah (صلى الله عليه و سلم ), we have heard from you today something which we never heard before"

He (صلى الله عليه و سلم )said When I climbed the first step, the angel Jibraeel appeared before me and said "Destruction to him who found the blessed month of Ramdhan and let it pass by without gaining forgiveness"upon that I said 'Aameen'.
When I climbed the second step, he said,"Destruction to him before whom thy name is taken and then he does not make Dua for Allah's blessing on me (by saying, for example صلى الله عليه و سلم )."I replied 'Aameen'.
When I climbed the third step, he said"Destruction unto him in whose lifetime his parents or either one of them reaches old age, and (through failure to serve them) he is not allowed to enter Jannah".I said 'Aameen'. (Hakim, Baihaqi)

Note In this Hadith, it appears that Jibraeel (AS) gave expression to three curses, upon which Rasulullah (صلى الله عليه و سلم) said Aameen every time. In al-Durr al-Mansoor it is reported that Jibraeel (AS) advised Rasulullah ( صلى الله عليه و سلم) to say Aameen. Being an angel of such high mark, Jibraeel 's giving these curses is sure to be accepted. May Allah () in His infinite mercy grant us His help and save us from these three dangers.Source