What is the miracle of Saint Joseph?

There are numerous prayers and devotions said to invoke the patronage of St. Joseph. Probably the most popular one is the following:

"To thee, O blessed Joseph, do we come in our tribulation, and having implored the help of thy most holy Spouse, we confidently invoke thy patronage also. Through that charity which bound thee to the immaculate Virgin Mother of God and through the paternal love with which thou embraced the Child Jesus, we humbly beg thee to graciously regard the inheritance which Jesus Christ has purchased by his Blood, and with thy power and strength to aid us in our necessities. "O most watchful Guardian of the Holy Family, defend the chosen children of Jesus Christ; O most loving father, ward off from us every contagion of error and corrupting influence; O our most mighty protector, be propitious to us and from heaven assist us in our struggle with the power of darkness; and, as once thou rescued the Child Jesus from deadly peril, so now protect God's Holy Church from the snares of the enemy and from all adversity; shield, too, each one of us by thy constant protection, so that, supported by thy example and thy aid, we may be able to live piously, to die holy, and to obtain eternal happiness in heaven. Amen."

Tan Books, a Catholic publisher, puts out a small booklet filled with the prayers and devotions specific to St. Joseph and is well worth finding or purchasing if you seek further devotions to this saint.