August Friedrich Wilhelm Sack

August Friedrich Wilhelm Sack (1703–1786) was one of the most eminent German Reformed preachers and a prominent liberal theologian of the reign of Frederick II of Prussia who helped shape the Enlightenment in Berlin and Prussia.

Life August Friedrich Wilhelm Sack was born at Harzgerode in the Principality of Anhalt-Harzgerode on 4 February 1703, the eldest son of the mayor of the town. In 1722–1724 he studied at Frankfort-on-the-Oder. The next two years he passed as tutor in the family of a French preacher at Stettin. Then he studied in Holland. Here he became acquainted with the chief theologians of Arminianism, from which his own views took a permanent colouring. From 1728 to 1731 he was teacher to a young prince in the neighbourhood of Magdeburg. In 1731 he began to preach in Magdeburg, and rapidly rose in esteem and in office.

Works The chief theological work of Sack is Der vertheidigte Glaube der Christen (issued first in 1751, again in 1773), a popular statement and defence of Christian doctrine. In this work, says John Powers Lacroix, the author ably and safely avoids the two fatal extremes of dynamic determinism as to the action of grace and of the self-regeneration of the Socinians. "The objective conditions of salvation are miraculously prepared in redemption; the subjective appropriation of these conditions is left to human freedom. God cannot convert man without man; man cannot convert himself without God."

Of Sack's sermons several volumes appeared (1735 to 1764). They passed through many editions. One volume of them was translated into French by Frederick II's queen, Elizabeth: Six Sermons de M. Sack (1775).