Legend has it that the hermit Fra Joan Garí was commissioned to remove from the devil the body of Count Guifré's daughter. But the devil tempted him and Fra Garí raped and murdered the Count's daughter. Once he realized what he had done, he went to Rome to seek forgiveness from the Pope. He heard the story of Fra Garí and forgave him his terrible sins by imposing a penance on him: I had to walk four staples until a child said to him, "Garí, stand up, your sins are forgiven."
Fra Garí returned to Montserrat fulfilling the penance imposed by the Pope. He arrived curved and with his body so deformed that he almost didn’t look like a man. Count Guifré organized a hunt for Montserrat and there they found Fra Garí. No one recognized him and they were so amazed at his appearance that they took him to Barcelona in a cage to exhibit him at the Court. Days later, Count Guifré's wife gave birth to a son who eight days later approached Fra Garí's cage and told him "Garí, stand up, your sins are forgiven".
Guifré and Garí went to Montserrat, where Garí had buried the Count's daughter. There they exhumed the remains to take them to Barcelona and miraculously found the girl’s incorrupt body. She had been saved by the Virgin at the last moment.
The Fra Garí cave is located next to the cliff and about twenty meters high on the Camí de Sant Miquel.
You can find more information in the book: REDO MARTÍ, SALVADOR. Montserrat and its surroundings. Editorial angle. Collection Places (1). Manresa, April 1996.