Click here to pray. This will impress the citizens, who would otherwise charge you with heresy (which could result in large fines). You can wait for the sermon to end, though it's not required.
Feeding the poor
You can donate some food to attract more beggars to the town. If you donate enough to get the "An extremely generous donation!" message, a large number of beggars will gather during the next few days. Some of them will settle in the city and will try to get a job in one of your workshops (four beggars for every worker).
The amount needed for a "generous donation" depends on the stock of goods in the city, town population etc. Early on, it's enough to donate a few loads of grain or fish. Later, slightly larger amounts will be necessary. In older versions of the game, players used to donate a number of beer on the first day, and one barrel of beer every day afterwards. This trick would ensure a steady supply of beggars.