When Paul and Barnabas were returning to towns which had already received the Gospel, what did they tell the believers? What was the follow up? They returned "strengthening the souls of the disciples, encouraging them to continue in the faith, and saying that through many tribulations we must enter the kindgom of God" (Acts 14:22).
That sounds very similar to discussions among the workers among the Dong people. One worker recently thought aloud, "Maybe we should warn people before they even believe: faith in Christ is going to cost them; they will be persecuted."
How do we prepare hearts for tribulation, trials, and persecution? It is especially hard when those who are communicating the gospel have not themselves faced persecution (or do not feel like they have faced it).
Maybe it is as simple as the verse out of Acts says, just let them know. Because the world is fallen, because Christians who stand firm never fit in, because of so many reasons, there will be trials. And because Christ is worth more than all these things, we need not only to remind the Dong people of what they face ahead but to live out our witness of Christ in front of them.
Pray for the Dong Christians who are facing trials: questioning, harassment, confiscation of property, and restrictions on speaking of this great hope we have.