My friend who is catholic asked me to stand up in her wedding which will be in the Lutheran Church to her Lutheran fiancee, I do not know if she was confirmed Catholic, as a Catholic should I accept or decline?
To be in a wedding party is to be an offical witness to the validity of the wedding. As a Catholic you may not give witness to the wedding of another Catholic who is marrying outside of the Church. Such a marriage is invalid in the eyes of the Church.
Fr. Vincent Serpa, O.P.