Should we try to encourage users of BH.SE and †.SE to also participate on the other site?

I've noticed one active [BH.SE user](https://hermeneutics.stackexchange.com/users/68/jon-ericson) trying to [recruit people from here](https://christianity.stackexchange.com/users/914/jon-ericson?tab=activity) (or that's how I've interpreted it). IMO these two sites shouldn't be competing for users. So giving hints about the other site might be a good practice. On the other hand, I'd hope for the participation to go both ways.

Should all of us here become active on BH.SE, too? How can we get BH.SE people to participate here? Should we try?