Build one means divine love. Enter one, benevolence, honorable conduct. Pray in one, consolation and joy. To talk in one and disturb worship signifies envy, sin. Be seated in one means change of apparel. Listen devoutly, happiness if you follow the rules. Sing in the choir, melancholy.
Dream dictionary: pray in a church dream meanings
The cross is very spiritual symbol which shows your views towards the life. Perhaps you are trying to find the connection with the world that you are in. If you are very religious person, pray a lot, go to church often, it is very normal to dream about the cross. The cross is also a symbol of the end of something. In many cultures the cross is not only religious symbol, it also indicates the fact that something has come to an end.