Does Paritta/Sutta really have magical power?

Many people believed certain Paritta/Sutta have certain magical power, for example Bojjhanga Sutta for curing illness and Om Mani Padme Hum having a great (even greatest) magical power among other Mantra (i refer Mantra to Mahayana tradition and Paritta to Theravada tradition). What do you think about this? Does the Buddha has spoken **by Himself** - that His follower can re-chant his words (Sutta/Mantra) to gain specific magical power? If He has, please kindly tell me what Sutta is it, Note : Please dont be offensed, i love listening to Sutta, but im curious about this one.