We possess the work only in a Latin translation, which seems to have been made at a very early period, though there still exist some fragments of the Greek original, which have been collected by Fabricius (Cod. Apocryph. N. T. iii. p. 738) and Grabe (Spicileg. Patr. i. p. 303). The object of the author of this treatise is to instruct his readers in the duties of the Christian life, the necessity of repentance, man's relation to the church, fasts, prayer, constancy in martyrdom, and the like; but the manner in which he inculcates his doctrines is of a singular kind, for he represents them as divine revelations, which were made to him either in visions or by his own guardian angel, whom he calls pastor angelicus, and from whom his work derives its name. The whole.work is divided into three books: the first is entitled and contains four visions, which he pretends to have been ordered to commit to writing. The subjects are mostly of an ethical nature, or the church. The second contains 12 Mandata, which were given to Hermas by his guardian angel as answers to questions which he had put to him. The third book, entitled contains ten similes, which were likewise revealed to Hermas by his angel; and the similes themselves are taken from a tree and a tower. By these three means, visions, commands and similes, the author endeavours to show that a godly life consists in observing the commands of God and doing penance; that he who leads a godly life is safe against all temptations and persecutions, and will ultimately be raised into heaven. The objects of the writer were thus evidently good and noble, but some of his opinions have been very severely censured by theologians, and the character of the author has been the subject of lively controversies down to the present time. Most theologians are of opinion that, if not an impostor, he was at least a person of a weak understanding, but of a lively and enthusiastic imagination. Mosheim judges of him most severely, and treats him as a person guilty of a most unpardonable pious fraud, and whose production is of scarcely any value. The doctrines, however, are, on the whole, sound; and as to the form in which they are clothed, it is impossible for us to say what induced him to adopt it. The book itself is a sort of devotional treatise, and contains many a lesson, encouragement and warning, which must have been useful to the early Christians, and have comforted them under the sufferings to which they were exposed in those times. The high estimation in which the work was held is attested by Irenaeus (ad v. Haeres. 4.3), Clemens of Alexandria (Strom. 1.29), and Origen. (Explan. Epist. ad Rom. 16.) According to Eusebius (Hist. Eccles. 3.3), many indeed doubted the genuineness of the Pastor, but others had it read in public, and regarded it as a necessary introduction to Christianity. This latter was the case, according to Hieronymus (de Script. Eccles. 10), more especially in those countries where Greek was spoken; but Hieronymus himself is uncertain in his opinion, for sometimes he calls it a useful book, and sometimes a follish one. (Comment. in Habac. 1.1.) Tertullian (de Pudicit. 10), who had judged it very severely, does not appear to have made any deep impression upon his readers, for the fact of the Pastor being declared an apocryphal work by several synods, does not imply any opinion as to its value or worthlessness, but only shows that they did not regard it as a canonical work.

One of the main reasons why the Pastor was generally held in such high esteem was undoubtedly the belief that its author, Hermas, was the same as the one mentioned by St. Paul, an opinion which has been maintained in modern times by Dodwell, Wake, and others. But although there is no internal evidence to prove that the author of the Pastor was a different person, yet the uncertainty of the early church (see Tertull. l.c.; Euseb. Hist. Eccles. 3.25 seems to show that the author himself had given no clue to ascertain the identity, and perhaps intentionally avoided giving any. Another opinion, which is based on ancient authorities (Carm. c. Marcionem, iii. in fin.; Muratori, Antiq. Ital. mcd. aevi, iii. p. 853, &c.), is that Hermas, the author of the Pastor, was a brother of Pius II., bishop of Rome, who entered upon his office about the middle of the second century after Christ. But in the first place, the authorities on which this opinion is founded are of a very doubtful nature; and secondly, a writer of that time could not have avoided mentioning some of the heresies which were then spreading, but of which there is not a trace in the Pastor. Considering, moreover, that the work already enjoyed considerable reputation in the time of Irenaeus and Clemens of Alexandria, we must suppose that it was written either in the time of the apostles or soon after, and that its author was either the person mentioned by St. Paul, or one who assumed the name of that person for the purpose of acquiring a greater influence upon the minds of his readers.