According to the Book of Tobit, the archangel Raphael guided Tobias on his journey.
Tobias is sent by his father, Tobit, to recover money deposited with a relative in Media. Raphael appears in human form under the name Azariah and offers to accompany him. Tobias does not initially realize that his traveling companion is an angel.
During the journey, Raphael instructs Tobias to catch a large fish in the Tigris River. He explains that parts of the fish will help drive away the demon Asmodeus and later cure Tobit's blindness. Raphael also helps Tobias marry Sarah, whose previous bridegrooms had died because of the demon.
A common mix-up is confusing Raphael with Michael or Gabriel, who are also prominent named angels in Jewish and Christian traditions. Raphael is especially associated with healing and protection; his name is commonly interpreted as meaning “God heals.” The Book of Tobit is deuterocanonical in Catholic and Orthodox Christianity but is not part of the Jewish or most Protestant biblical canons.