Apocalypse Now
Father is super f*ucking creepy and once I heard Evrenol, the director, say that he modeled the character of Father on Kurtz from Apocalypse Now, it totally clicked: the madness, the god complex, the fanatic followers, the ideology in his rants- all there, totally Colonel Kurtz.
The film is far from perfect and it suffers terribly from plot and character development, but overall it is a great little independent horror film visually for such a low, low budget and the character of Father is phenomenal. The guy had never acted a day in his life and his delivery and movements were excellent.