Are "preaching to the choir" and "preaching to the converted" synonymous?

The following are acceptable expressions that I have heard:

"Preaching to the choir"

"Preaching to the converted"

To me, both mean essentially that you are trying to explain something to someone who already understands it. So you are wasting your time. (Edit: Although GEdgar's definition is better: "Arguing a controversial subject only with those who already share your opinion")

My friend is suggesting that there is a subtle difference in the meaning between the two. Is he right?

Edit: He suggests that the former has the implied context that very few people are listening- preachers normally preach to a congregation. The latter does not.

Solution 1:

They are essentially synonymous, but some could read some subtlety.

Both a choir and the converted are "true" believers, and therefore don't need to be preached to. But the converted are those who did not believe before, and believe now, whereas the choir could be those who always believed.

I don't think this is necessarily a big difference, but you may choose one over the other depending on your exact context.

Also, the OED notes a geographical difference:

• to preach to the converted and variants: to advocate something to people who already share one's convictions about its merits or importance. Also (orig. and chiefly U.S.) to preach to the choir.

Solution 2:

They are synonymous in their intended epigraphic meaning of 'exhorting people who are already convinced.

But there are some nuances.

• 'choir' is 'Christian'-centric (part of many Christian services which is a special section of the congregation is the choir).

• 'the converted' have a tendency to be more gung-ho than the life-time nothing-is-new members of the believers.

Solution 3:

I've always seen the difference as being that "preaching the choir" represents targeting people who have a stronger level of belief than the converted (with the congregation somewhere in between); since they've gone beyond simply being members to having made a commitment to attend regularly and participate in a more visible manor than the rest of the congregation.