Coccejus was born in Bremen as Johann Cock (from the German town of Coch or Goch). He studied languages, philosophy and theology in Bremen and after 1626 in Franeker. He became in 1630 professor at the Gymnasium Illustre in Bremen where he taught ‘sacred philology’ concentrating on Greek and Hebrew. In 1650 he moved to Leiden. As an orthodox Reformed or Calvinist theologian he also wanted to stay in touch with humanist trends in church and society. He showed often more interest in biblical studies than in strict Calvinist orthodoxy. He is best known for his divergent opinion in the observation of the Sabbath. According to him the rest of Sabbath was a strict command for the adherents of the Jewish religion, but in the New Covenant of Jesus Christ the observation of Sabbath was no longer so important. His interpretation of Scripture is sometimes characterised as ‘baroque, inconsistent’. Besides the puritan Voetius, the dominant professor in Utrecht University, he became the most outstanding theologian of Leiden University in the 17th century.
In Utrecht University Library I went to the section Special Collections and I found the most important text Coccejus wrote about Islam. Below my findings.
As a student of 22 years in Bremen, Coccejus held a lecture on the religion of the Turcs in Greek, partly as a linguistic exercise. This text (in print 11 pages) is written as an admonition for the reformation of church and state of his time. The origin and enormous progress of Islam in his time was a great challenge for the Christian peoples. From secondary sources a life of Muhammad and the content of the Qur’an is given. Coccejus considered Islam as a mutatio religionis, a radical transformation of the true religion. Muhammad knew the real truth of God’s revelation but he has been seduced by the Satan (‘the clear enemy of the whole human race as he is rightly called in the Qur’an’). So Muhammad and his followers have become renegades (apostatae). Muslims must be counted among the heretics. The divinity of Christ was the great issue in the debate with the Jews, and later with the followers of Paul of Samosata, the Arians, the Sabellians and later again the Muslims. He considers Islam as the great outer enemy of Christianity, where the Roman Catholic church is the great inner enemy. In his later theology Coccejus developed an interpretation of the history of Christianity in seven periods. The last is that of the conversion of the Turcs to Christianity (already predicted in the Scripture). The Roman Catholic Church, an instrument of the Anti-Christ will be destroyed with the help of the Turcs. As a sign of the soon return of Christ, Jews and Muslims will together celebrate the feast of Soekot/Tabernacles in Jerusalem. In this way Coccejus gave Islam a clear place in his eschatological vision. In the earlier Oratio this is not so outspoken. Especially in later exegetical treatises Coccejus applied texts of the Hebrew Bible to contemporary Islam. Isaias 45:14 about ‘the tall Sabeans .. will bow down before you’ refers to the great power of the Ottoman empire, but also predicts their coming conversion. The four wings of the beast of Daniel 7:6 refer to the four realms of the Roman Empire which were conquered by the Muslims: Syria, Africa, Asia and Greece. The ‘kings from the East’ of Rev. 16:12 were by him seen as the preparation for the end of time, when the ‘Turcs will come to the West again and all efforts will be made to preach the Gospel to them, so that they may convert.’ The peace of Westphalia (1648) was a beginning for this process and so the end of the world was expected in 1667 with the final triumph of the Reformed Church in a common service to God.