whats this movie's name?!!

hey sry for my english...i try to find the movie that i cant remember the name,the genre is horror n i just remind a few scene,its about the man who lost some one and in the burial ceremony of that person he ruined his cross in his hand and lost his faith,after that a demon followed him and i think he made a sound like a horse,at the end a father who helped him possessed by that demon and he exorcism the father and found he called the demon in that ceremony,at the end movie said that that guy(he is a father now) is teaching exorcism in some university now