Prayer and scriptural fellowship principles
If a non-WELS Christian leads a prayer with other non-WELS Christians and this person only reads the Lord's Prayer as the prayer, does this still constitute corporate prayer and therefore would preclude a WELS Christian from participating in the prayer? If there is more to the person's prayer, would it be wrong to participate in only the part in which the Lord's Prayer is recited?
It is not the content of a prayer or the form of a prayer that determines whether or not we pray with others. The usage of a common prayer does not suspend scriptural fellowship principles (Romans 16:17-18; Ephesians 4:3-6; 2 John 10-11).
We pray with others when there is oneness in faith. And when there is unity of faith, we can pray with a familiar prayer, like the Lord’s Prayer, or with other prayers.