One of the first major Syriac authors, Aphrahat wrote his Demonstrations in the middle of the long reign of Shapur II, and during a period of intense conflict between Persia and Rome. His intended readers were the so-called 'covenanters', representing a native Syriac form of ascetic life which would only later be influenced by Greek models. His Demonstrations are a mix of practical guidance, polemic against the Jewish community, and occasional exhortations to the Persian Church as a whole, all saturated with biblical exegesis. What makes his work unique is that the worldview he represents is only marginally hellenized, much closer to its Jewish roots than most other forms of Christianity in his day.

The first ten of the twenty-three sections of the Demonstrations were written in 337, many of them devoted to standard themes: faith, love, fasting, prayer, ascetic vows, repentance, and humility. This first group also includes a veiled discussion of political events of the day, "On Wars", as well as treatments of the resurrection and the role of church leaders.

The next twelve Demonstrations were composed in 344. Most of these engage in polemical arguments against Jewish positions on circumcision, Passover, the Sabbath, food laws, the status and future of the Jewish people, the status of Christ, the legitimacy of celibacy, and the meaning of persecution. In addition, there is teaching on almsgiving, a reflection on death and the end times, and a long exhortation to the leadership of the Persian Church. The very last Demonstration was written in the following year, and is Aphrahat's attempt to compile a 'geneology of the righteous'. The closing sections of this last Demonstration contain some of the most compelling passages in the work.