Jamieson, Fausset and Brown on Acts 15:40

40. and departed, being recommended ... to the grace of God--(No doubt by some solemn service; see Ac 13:3), as in Ac 14:26. It does not follow from the historian's silence that Barnabas was not so recommended, too; for this is the last mention of Barnabas in the history, whose sole object now is to relate the proceedings of Paul. Nor does it seem quite fair (with De Wette, Meyer, Howson, Alford, Hacket, Webster and Wilkinson, &c.) to conclude from this that the Church at Antioch took that marked way of showing their sympathy with Paul in opposition to Barnabas.