What is a miracle?
A miracle is a supernatural event which goes beyond the productive power of nature and implies a special intervention of God and at the same time it is a sign and manifestation of the message [...] If it is a healing it must be instantaneous, complete and lasting and cannot be explained according to the law of nature and in the light of present medical knowledge. The Church requires miracles for beatification and canonization because they are a kind of 'seal' which God affixes to his servant and through which he guaranties his sanctity. The examination of presumable healings begins with medical investigation, i.e. by physicians, then theologians present their opinions and finally the theologians are expected to issue a statement that the healing, which the physicians cannot explain, is a true miracle of God attributed to the intercession of the Servant of God or the Blessed. The last word belongs to the ordinary meeting of cardinals and bishops and in the end the promulgation of the decree by the Holy Father follows.
"Niedziela" 22/2005 - Czekamy na nowego Swietego Polaka - Jana Pawla II