Bishop Bertram Meier of Augsburg called on his listeners to "become Advent people".
In the face of current crises and hardships, Advent people do not simply believe "that everything will somehow be all right".
Instead, they rolled up their sleeves where they were needed. The secret is not to feel sorry for others, but to encourage them.
"We all need Advent people who don't talk down to us, but believe in us," said Meier, explaining the campaign motto. "God thinks so highly of us that he makes himself small in order to give us a horizon that is greater than any despair."
Meier spoke during a sermon in the Augsburg suburb of Königsbrunn.
Developing self-confidence
Adveniat campaign partners from Colombia took part in the service, including the German theologian Ulrike Purrer. She went to school in Königsbrunn and has been running a church youth centre in Tumaco, a city with a high crime rate, for ten years.
The centre is "a place where children and young people can develop self-confidence through play and artistic and cultural projects and thus escape the spiral of violence and drugs through their own efforts", said the bishop.
The donations on 24 and 25 December at all Catholic Church services in Germany will benefit the Latin American aid organisation Adveniat.
Its Christmas campaign also has a political thrust.
Together with its partners in Latin America and the Caribbean, the aid organisation is calling on governments to respect the United Nations Convention on the Rights of the Child. This states that children have the right to education, schooling and social security.
However, the reality for many young people in the region is very different.