Luther’s theological anthropology with its emphasis on radical understanding of (original) sin and on lacking liberty, as far as salvation is concerned, is most prominent in his discussion with Erasmus of Rotterdam. Luther’s views require a discriminate approach. His critical view of the capabilities of human reason stems from soteriological emphasis on salvation as God’s activity for the sake of humans. Luther’s positive appraisal of human reason was developed in the context of his doctrine of two realms. Natural law as the Golden Rule is seen as a suitable ethical principle in searching for justice and welfare in human society – for Christians and Non-Christians alike. The author points out to the secular aspects in Luther’s theology and underlines his positive judgment of the society governed by reason.