Kalthoff criticized what he regarded as the romanticist and sentimental image of Jesus as a "great personality" of history developed by German liberal theologians, including Albert Schweitzer who noted Kalthoff in his work The Quest of the Historical Jesus.
Kalthoff mengkritik apa yang ia anggap sebagai romantisis dan gambaran sentimental Yesus sebagai "personalitas besar" sejarah yang dikembangkan oleh teolog-teolog liberal Jerman, termasuk Albert Schweitzer yang dicatat Kalthoff dalam karyanya The Quest of the Historical Jesus.