St. Luke is regarded as the patron of physicians and surgeons. He wrote one of the major portions of the New Testament, a two-volume work comprising the third Gospel and the Acts of the Apostles. In the two books he shows the parallel between the life of Christ and that of the Church. He is the only Gentile Christian among the Gospel writers. Tradition holds him to be a native of Antioch, and Paul calls him "our beloved physician" (Col 4:14). His Gospel was probably written between C.E. 70 and 85.
Luke appears in Acts during Paul’s second journey, remains at Philippi for several years until Paul returns from his third journey, accompanies Paul to Jerusalem and remains near him when he is imprisoned in Caesarea. During these two years, Luke had time to seek information and interview persons who had known Jesus. He accompanied Paul on the dangerous journey to Rome where he was a faithful companion. "Only Luke is with me," Paul writes (2 Tim 4:11).
The Gospel text chosen for the feast is the Mission Discourse to the seventy (seventy-two). These number seventy/seventy-two seems to have their origin the list of nations in Gen 10, where the Hebrew text lists seventy nations and the Septuagint lists seventy-two. It may also recall Moses’ appointment of seventy elders to help him (Exod 24:1; Num 11:16, 24). The more likely interpretation, however, is that the number is related to the biblical number of the nations (Gen 10), so that the commissioning of the seventy/seventy-two foreshadows the mission of the church to the nations (Lk 24:47). In these verses Jesus instructs his disciples how they are to do Mission and conduct themselves in Mission. The key to Mission is detachment. The disciples are to be detached from things, persons and place. They are also to be detached from the outcome of Mission. They must constantly keep in mind that the Mission is the Lord’s and not theirs.