It is perfectly fine to attend one and not the other. Make sure to let the parents know as soon as possible though.

If you cannot attend the ceremony, you cannot attend the ceremony. Just be syre to great the honoroed guest and his parents with apologies for not being able to attend the ceremony, and wish your heartfelt congratulations.

When I was in high school, I was invited to a Ba Mitzvah (sorry about spelling). I only went to the reception, not the ceremony and no one cared. We told them ahead of time of course.

If you have been invited it is because you are a friend.

You are clearly not Jewish, and I’m sure the host knows that. I don’t think anyone expects you to be familiar with the customs of a religion that you do not practice.

Why are you asking random strangers what would offend your friend? Why not ask the host? Doesn’t that seem to be the most logical way to handle this?

I would just casually tell the parents that you are busy Friday but would like to be there Saturday. It would really vary from family to family.

A lot of people came to my reception who were not there for my bar mitzvah service. I didn’t mind at all. I was just glad to see people.