Question:
Is there anything wrong with inviting the so-called “laboring or traveling brothers” to come and minister?

Answer:
“A vision appeared to Paul in the night; “There stood a man of Macedonia and prayed him, saying, Come over into Macedonia and help us. And after he had seen the vision, immediately we endeavored to go into Macedonia, assuredly gathering that the Lord had called us for to preach the gospel unto them” (Acts 16:9).

Receiving a vision is not quite the same as receiving a letter or phone call; but perhaps the principle is the same. The “laborers” often receive such invitations, or at least subtle or not so subtle reminders of how long it has been since they have last visited a certain assembly. Of course, the servant of the Lord must always be before the Lord as to what He would have him to do, what assemblies he should visit and when, what he should minister at each assembly, etc. But if an assembly is having a particular problem and desires ministry directed toward the problem, it would seem particularly appropriate to notify one or more of the “laborers” for their prayer and consideration of a ministry visit.