Whatever man uses without the fear of God, whatever he applies to the mere gratifying of his flesh, cannot fail to operate as a poison to the soul, however pleasant and salutary it may appear to be to the body.

His principal work Wahres Christentum (book 1: 1605; books 1-4: 1606-1610) i. At Wittenberg the crypto-Calvinist controversy was then at its height and he took the side of Melanchthon and the crypto-Calvinists. After Wahres Christentum Arndt's best-known work is Paradiesgärtlein aller christlichen Tugenden which was publiJohann Arndtd in 1612.

Johann Arndt (or Arnd; 27 December 1555 – 11 May 1621) was a German Lutheran theologian who wrote several influential books of devotional Christianity.