METANOIA. Literally repentance or penance. The term is regularly used in the Greek New Testament, especially in the Gospels and the preaching of the Apostles. Repentance is shown by faith, baptism, confession of sins, and producing fruits worthy of penance. It means a change of mind from unbelief to faith, and a change of heart from sin to the practice of virtue. As conversion, it is fundamental to the teaching of Christ, was the first thing demanded by Peter on Pentecost, and is considered essential to the pursuit of Christian perfection. (Etym. Greek metanoein, to change one's mind, repent, be converted, from meta- + noein, to perceive, think, akin to Greek noos, nous, mind.)