Jamieson, Fausset and Brown on Acts 28:21-22

21-22. We neither received letters out of Judea concerning thee, &c.--We need not suppose (with Tholuck and others) that there was any dishonest concealment here. The distinction made between himself, against whom they heard nothing, and his "sect," as "everywhere spoken against," is a presumption in favor of their sincerity; and there is ground to think that as the case took an unexpected turn by Paul's appealing to Cæsar, so no information on the subject would travel from Jerusalem to Rome in advance of the apostle himself.