To what shall I compare the kingdom of God?
It is like a Walmart store, where any on-the-clock employee who sees a spill on the floor immediately becomes responsible for it. It doesn't matter if he or she is a custodian, greeter, or even the store manager. It doesn't matter if he or she works in management, security, or human resources. It doesn't matter if he or she works on the loading dock, at the register, in food or lawn & garden or sporting goods or women's wear.
Whoever they are, wherever they were headed, whatever may have caused it, when a Walmart associate sees a spill he or she is expected to stand over it, point at it, and warn others not to walk through it--at least until a second employee comes along. Then the two of them can set up a hazard sign and clean up the spill.
Let him hear who questions whether Christians should point out false doctrine...