One of the reasons for this appellation is because thousands of people have asked his intercession over the centuries and have received a miraculous response to their prayers.
However, it is important to remember that God is the author of the miracle, while St. Anthony is simply an instrument. God’s response may not always be what we expected or wanted, but he always grants us exactly what we need, and sometimes in a miraculous way.
Here is a popular prayer to St. Anthony that is called by many the “Miracle Prayer.”
Dear St. Anthony, your prayers obtained miracles during your lifetime. You still seem to move at ease in the realm of minor and major miracles. St. Anthony, Performer of Miracles, please obtain for me the blessings God holds in reserve who serve Him. Pray that I may be worthy of the promises my Lord Jesus attaches to confident prayer.