I live a few miles from the international headquarters of a oneness Pentecostal ecclesial community. A friend of mine is one of them. She says the Trinity is like roles. For example, she is a wife, mother and daughter. One God, one person.
I was trying to defend the doctrine of the Trinity. I mentioned that at the baptism of Jesus, the Father says, “This is my son in whom I am well pleased.” Also, the Holy Spirit descended like a dove. All three persons of the Trinity are mentioned.
Next, I asked her to whom Jesus offered his sacrifice on the cross. If he offered it to himself, it is not a proper sacrifice. Sacrifices are offered to someone else.
I said that the Bible teaches three persons in one God then named some of them.
Nothing I said convinced her.
On many other things, we agree because I am a charismatic Catholic.
What else could I have said to convince her?