"Then he led them out as far as Bethany, and lifting up his hands he blessed them. While he blessed them, he parted from them and was carried up into heaven. And they worshiped [bowed down] him and returned to Jerusalem with great joy, and were continually in the temple blessing God." (24:50-53)
What does Jesus' blessing here mean? Some have pointed to Leviticus 9:22, which portrays Aaron raising his hands as he blesses the people, as the background to Jesus' blessing of the disciples, even suggesting that Jesus may have blessed them with the priestly blessing of Numbers 6:24-26. Some scholars, like Dennis Hamm, have seen an additional allusion to a passage from Sirach. Sirach (A.K.A. Ecclesiasticus, A.KA. The Wisdom of Jesus Ben Sira) is a 2nd century B.C.E. Palestinian Jewish writing which was very influential among ancient Jews and Christians and is considered scriptural by the Roman Catholic and Orthodox churches. Near the end of the book we read this description of the high priest Simon that :
"Then Simon came down, and lifted up his hands over the whole congregation of the sons of Israel, to pronounce the blessing of the Lord with his lips, and to glory in his name; and they bowed down in worship a second time, to receive the blessing from the Most High. And now bless the God of all, who in every way does great things; who exalts our days from birth, and deals with us according to his mercy. May he give us gladness of heart, and grant that peace may be in our days in Israel, as in the days of old." (Sirach 50:20-23; to read the whole chapter click here.)
Dennis Hamm has this to say:
"Contemporary readers, familiar with blessings at the end of services, easily take [Jesus'] blessing simply as a gesture of farewell and dismissal. In the world of first-century Palestine, however, raising one's hands and pronouncing a blessing . . . were the actions of a priest of the temple, most commonly as part of the twice-daily Tamid service. Then comes the disciples' worship [prostration] of Jesus and their return with joy to Jerusalem, where they regularly bless God in the temple. It is this combination of these elements -- the raising of the hands, the blessing, and the response of the community in joyful worship -- that has led such commentators as Daube, van Stempvoort, and Brown to recognize here an allusion to the portrait of the high priest Simeon II in Sir 50:20-23 . . .
Luke 24:50-53 echoes at least five features of that passage: (1) the raising of the hands (Sir 50:20a // Luke 24:50); (2) the blessing (Sir 50:20b // Luke 24:50-51a); (3) the worshipful prostration (Sir 50:21 // Luke 50:51b); (4) the blessing or praising of God (Sir 50:22a // Luke 24:53); and (5) the note of joy (Sir 50:23: a prayer for joy of the heart // Luke 24:52b: disciples return to Jerusalem with great joy). The occurrence of this complex of five elements (and I will suggest a sixth) both at the end of Luke's Gospel and at the climax of Ben Sira's panegyric makes it plausible, even likely, that Luke describes the departure of the risen Jesus and the disciples' response in a way that is meant to evoke the memory of Sirach's description of the high priest Simeon blessing the people of Israel." ("The Tamid Service in Luke-Acts: The Cultic Background behind Luke's Theology of Worship [Luke 1:5-25; 18:9-14; 24:50-53; Acts 3:1; 10:3, 30]" Catholic Biblical Quarterly 25: 2003, 217-218).