Which is this sutta, which describes a monk prepared to travel and to experience violence?

A [tag:reference-request] question. Which sutta contains the following story? - It starts with a monk who will travel to a far land (perhaps to a state on the west coast of what's now India, and perhaps as a missionary). The Buddha asks, how will he react if he's attacked? - It ends with the monk's saying that he will reflect that death is something which some (other) people seek, that these people have to arrange to find a murderer who will kill them, and that the people killing *him* have saved him this trouble! And in that way, he'll keep a mind of good-will. - The Buddha approves. I remember it as similar to the parable of the saw; perhaps a much shorter sutta.