My friend from work is baptizing his son next month. I have been invited to the baptism, but it is during their service. My question is what am I to do, as a faithful practicing Catholic and am I even allowed to attend the service?
You may attend since the purpose of attending the service is not to worship with your friend, but to witness the baptism (valid) of his son.
“According to the local situation and as occasion may arise, Catholics may, in common celebration with other Christians, commemorate the baptism which unites them, by renewing the engagement to undertake a full Christian life which they have assumed in the promises of their baptism, and by pledging to cooperate with the grace of the Holy Spirit in striving to heal the divisions which exist among Christians.”
Here are a few “do’s and don’ts” for Catholics attending liturgical celebrations in other ecclesial Communities:
**DO—**Take part in the psalms, responses, hymns and common actions of the Church in which you are a guest. (ibid no. 118 --provided they do not conflict with Catholic teaching)
**DO—**Take part in the Lord’s Prayer, Apostles’ Creed, Nicene-Constantinopolitan Creed, a Trinitarian Doxology, the Glory to God in the Highest (ibid no. 187)
**DON’T—**Receive communion in Churches or ecclesial communities not in full communion with the Catholic Church. (ibid no. 129)