Germany's cardinals used their Christmas sermons on Monday to call for greater solidarity in German society.

Cologne cardinal Rainer Woelki said that Germany's increasingly strained social cohesion was the fault of a housing market that had become buoyed by property speculators and a lack of affordable housing.

Read more: Refugee boat serves as altar in Cologne

"More and more people can no longer afford to live in this prosperous country because many apartments are being used exclusively as a means of making profit, thus making them more expensive and creating a lack of affordable housing," Woelki said.

Woelki decried the practice as cynical and even inhumane. A community, he added, cannot function if average earners can no longer afford to own somewhere to live.

Read more: Property boom in Germany as investors choose real estate over stocks

God was incarnated as a German

Heinrich Bedford-Strohm, the chairman of the Council of the Protestant Church in Germany, dedicated his Christmas sermon to warn against the "virus of nationalism, xenophobia and religious fanaticism."

Bedford-Strohm, the highest representative for German Protestants, said: "The joy of Christmas, as it's experienced around the globe, shows that God will not be incarnated as a German, American, Russian or Chinese, but as a human.

Meanwhile, the chairman of the German Bishops' Conference, Cardinal Reinhard Marx, insisted that the Christian Christmas holiday could provide the answer as to what keeps society held together. "If I believe that God, embodied through Jesus, became everybody's brother, that then strengthens my own attachment and openness, as well as my willingness to show solidarity and work with others," Marx said.

dm/jm (dpa, AFP, epd)