A striking feature of the angel’s greeting is that he does not address Mary with the usual Hebrew salutation shalom – peace be with you – chaíre, which we might well translate with the word “Hail,” as in the Church’s Marian prayer, pieced together from the words of the annunciation narrative (cf. Lk 1:28, 42). Yet at this point it is only right to draw out the true meaning of the word chaíre: rejoice! This exclamation from the angel – we could say – marks the true beginning of the New Testament.Pope Benedict XVI Pope Benedict XVI
The word reappears during the Holy Night on the lips of the angel who says to the shepherds: “I bring you good news of great joy” (Lk 2:10). It appears again – in John’s Gospel – at the encounter with the risen Lord: “the disciples were glad when they saw the Lord” (20:20). Jesus’ farewell discourses in Saint John’s Gospel present a theology of joy, which as it were illuminates the depth of this word. “I will see you again and your hearts will rejoice, and no one will take your joy from you” (16:22).
Joy appears in these texts as the particular gift of the Holy Spirit, the true gift of the Redeemer. So a chord is sounded with the angel’s salutation which then resounds throughout the life of the Church. Its content is also present in the fundamental word that serves to designate the entire Christian message: Gospel–good news
Source: Jesus of Nazareth: The Infancy Narratives (2012)