Becoming the rector of the local Latin school, he was appointed to his satisfaction in 1657 as a pastor in Oosterlittens (Littenseradiel), and started as one of the first to preach on Sunday afternoon.
In two months time Bekker visited London, Cambridge, Oxford, Paris and Leuven, with a great interest in the art of fortification.
[1] An enthusiastic disciple of Descartes, he wrote several works on philosophy and theology, which by their freedom of thought aroused considerable hostility.
[4] His best known work was De Betoverde Weereld (1691), or The World Bewitched (1695), in which he examined critically the phenomena generally ascribed to spiritual agency.
The orthodox among Dutch theologians saw his views as placing him among notorious atheists: Thomas Hobbes, Adriaan Koerbagh, Lodewijk Meyer and Baruch Spinoza.
Jacob defined them as "pantheist, freemasons and repubblicana" characterized by a Radical criticism of religion that "anticipated Dutch 'Patriots' and Enlightment philosophers in the late eighteenth century "[11] In July 1698 he was elected a Fellow of the Royal Society of London.