This prayer of repentance is attributed to Manasseh, the son of Hezekiah who is credited with the wickedest reign in the history of Judah (687-642 B.C.) According to 2 Chronicles 33:1-20, late in Manasseh’s reign the king was taken captive by the Assyrians. While in captivity, he remembered his God and prayed to him. No prayer is recorded, but we are told the Lord listened to him and restored him to his kingdom.

Since the Prayer is based on Chronicles, it must be dated after the fourth century B.C., but it seems unlikely to have been the product of Christian writers. There are several scholars who think the book was written by the author of the Apostolic Constitution (OTP 2:627), making the date prior to the fourth century A.D. But as Charlesworth says the author “was obviously a Jew.”
The earliest reference to the Prayer is in the third century A.D. Didaskalia, a Christian retelling of 2 Kings 21 and 2 Chronicles 33. Although this prayer was never part of the Septuagint nor did it appear in it does not appear in Vaticanus or Sinaiticus, it is often included in introductions to the Apocrypha.. The origin of the Prayer is almost impossible to determine in such a short book with no cultural or historical references.
Since the work is based on 2 Chronicles 33 and the psalms of repentance like Psalm 51, the value for New Testament studies is limited. Perhaps a “theology of repentance” could be developed based on this Prayer, Psalm 51 and other Pseudepigrapha books such as Joseph and Aseneth which might illustrate the New Testament idea of repentance and highlight difference between the Jewish idea and the developing Christian view of repentance (if any).
The book is very vivid in its description of repentance. The writer says that he will “bend the knee of my heart, imploring you for your kindness” (vs. 11). The Prayer of Manasseh was collected by Christians along with a number of other biblical prayers and odes. This prayer collection is found in Codex Alexandrinus (fifth century) and Codex Turicensis (seventh century).
Because you are the Lord, long-suffering, merciful, and greatly compassionate; and you feel sorry over the evils of men. You, O Lord, according to your gentle grace, promised forgiveness to those who repent of their sins, and in your manifold mercies appointed repentance for sinners as the (way to) salvation.
You, therefore, O Lord, God of the righteous, did not appoint grace for the righteous, such as Abraham, Isaac, and Jacob, those who did not sin against you; but you appointed grace for me, (I) who am a sinner. (translation Charlesworth).
Aquinas used the Prayer of Manasseh to argue the sacrament of Penanceis is a necessary condition for all who are in sin (Summa Theologiae, 3a.84.5). Martin Luther told the Duke of Braunschweig he should “in all sincerity genuinely repent,” using “words such as those that appear in the Prayer of Manasseh” (OTP 2:632).

These four songs may have been part of a larger liturgical collection, but only these four survived in the Cairo Genizah in a tenth century manuscript. Despite this, many consider these psalms to come from a much earlier period, possibly the Qumran community. As Lorein and van Staalduine-Sulman comment, this is possible but no definitive proof exists for these Psalms originating with the Qumran community. In fact, the eschatological use of David in the psalms seems to point more toward the Targum and early rabbinic writings than Qumran (MNS, 261). Nevertheless, As Lorein and van Staalduine-Sulman conclude an origin for these psalms in the later-Qumran period “seems a valid option” and suggest these psalms were among the manuscripts discovered at Qumran about A.D. 790 and were taken to the Qaraite community in Cairo around A.D. 800.
It is difficult to date the book, although a date in the fourth century A.D. is a reasonable guess (OTP 2:585). Jones suggests the third century A.D. following the more recent work of Baarda and de Vos. It is possible the suggestion in line 37 to teach your brutish son to become a gladiator and hope he dies young implies a pre-Constantine date (Baarda, 2:585) since “schools for gladiators” began to disappear in the late fourth century. But even this evidence is weak since the metaphor of a brutish gladiator would have continued to be effective for some time after the heyday of the gladiatorial games.
Unlike this Roman attitude toward manual labor, the Second Temple wisdom literature represented by Pseudo-Phocylides valued hard work. Paul reflects this Jewish wisdom worldview and it eventually it becomes the Judaeo-Christian work ethic. For example, “You shall eat the fruit of the labor of your hands; you shall be blessed, and it shall be well with you” (Psalm 128:2, ESV). “Sweet is the sleep of a laborer, whether he eats little or much, but the full stomach of the rich will not let him sleep” (Eccl 5:12). This view is also reflected in later Jewish literature as well: “Do not hate hard labor or farm work, which was created by the Most High” (Sirach 7:15). In the Talmud, “He who does not teach his son a craft teaches him brigandage” (Kiddushin 29a).