He is mentioned in the Epistles of St Paul (Romans 16:14). He served as a bishop in the first-century Church, and died a martyr. His book, The Shepherd, is one of the earliest Christian writings outside of the New Testament, and was held in such esteem by the early Church that it is sometimes found in ancient collections of the Holy Scriptures.
Hermas had been a wealthy man, but had fallen into poverty through his sins. A man, clad all in white and holding a staff, appeared to St Hermas and, telling him that he was an angel of repentance, gave St Hermas twelve commandments: To believe in God
To live in simplicity and innocence
To love truth and flee from falsehood
To guard his thoughts in chastity
To learn patience and magnanimity of soul
To know that a good and an evil spirit attend every man
To fear God, but not the devil
To perform every good deed and to restrain himself from every evil one
To pray to God in faith from the depths of his heart, so that his prayer might be heard
To preserve himself from melancholy, the daughter of doubt, and from anger
To try true and false prophecies
To preserve himself from every evil desire.