What Do You Do When Someone Takes God's Name in Vain?

I also understood it to be about heresy, false teaching.

The Jews would teach morality and doctrine in the Name of Yahweh, but there were often false prophets who sprang up teaching novelties and falsehoods. They would also take the Name, but in vain. Therefore, to teach error is to take the Name of the Lord in vain. This seems to be a minority interpretation now, and I believe it is even omitted from the Catechism.

Insofar as a lying prophet takes the Name in exercising the office, it would indeed violate the Commandment quite directly.

If you have doubts about the gravity of a sin why not ask your parish priest? Pax

DISCLAIMER: The views and opinions expressed in these forums do not necessarily reflect those of Catholic Answers. For official apologetics resources please visit www.catholic.com.