By what authority does the Catholic Church make Saints?

The Catholic Answers

The decree of canonization does not make a Saint. It simply declares infallibly that a given person has lived such a holy life with the help of God’s grace that he is a Saint. When someone like a Francis of Assisi lives such a holy life that all people are compelled to admire it, the Church is often asked to say whether such a person is worthy to be honored publicly as a Saint. The Church then carefully collects all possible information, and, after due consideration, says yes or no. If the Church says yes, the name of the person to be venerated is put into the Canon or catalogue of those who have become Saints by their heroic lives of virtue. The Church has the authority of Christ for these decisions, for He sent her with His authority to teach all nations in matters of faith and morals, and she could not tell us officially that a given person was a perfect model of Christian virtue if such a person were not.

Radio Replies Volume 1 by Rev. Dr. Leslie Rumble MSC and Rev. Charles Mortimer Carty