2 Corinthians 8:19

And not only so, but who was also appointed by the churches to travel with us in the matter of this grace, which is ministered by us to the glory of the Lord, and to show our readiness.

These are further remarks about the "brother" whose fame through all the churches was in the gospel. Luke was Paul's constant traveling companion; and in the word here that the churches had appointed someone to travel with Paul, there is strong inferential support for the view that he was none other than Luke. The good sense of the churches in appointing a physician to this task is evident, and this would also explain who paid Luke's charges for those long years of his abandonment of his medical practice for the purpose of traveling with Paul. The real objections that some scholars have to this view is that it blows their late dating of the Gospel of Luke right out of the water. If one is not married to the theory of a late date for Luke, the supposition that Luke is probably the one Paul mentioned here is quite reasonable.