The Babylonians destroyed the Temple of Jerusalem in 587 BC and took most of the people of Israel into captivity—moving them from their ancestral home to foreign lands.  Psalm 137 engages the feelings of those displaced persons (v. 1).

By the rivers of Babylon
there we sat weeping
when we remembered Zion.

The exiles poured out their desolation at the separation from their homes but especially from the center of the faith of their forbearers.  They resolved never to forget where they came from or to whom they belonged (vv. 5-6):

If I forget you, Jerusalem,
may my right hand forget.
May my tongue stick to my palate
if I do not remember you,
If I do not exalt Jerusalem
beyond all my delights.

Some 500 years later, we find Mary and Joseph in Egypt as they flee from Herod with the holy child in arms.  We can hear Mary joining with Joseph in singing this song—Psalm 137—with increased and personal fervor.

Remembering Jerusalem with its Holy Temple and its rich history for the Jews would sustain Joseph and Mary in their exile.  They would resolve to be faithful to the God who had acted on behalf of his people.  That place of God’s dwelling and revelation could never fade from their hearts. As they prayed this psalm, as they remembered the Lord’s deliverance of a chosen people from the Babylonian exile, they could find comfort in the way in which God cared for their ancestors and reestablished them in their homeland.  They could believe that he would do the same for them.  The Gospel-writer Matthew finds particular emphasis in his recalling of the story of the Exodus as he repeats the words of Hosea 11:1, “out of Egypt I have called my son” (Mt 2:15).

In her Annunciation story, Gabriel presents himself to Mary with the greeting “Hail, favored one! The Lord is with you”(Lk 1:28).  These words highlight the faith of Mary.  In his Annunciation story, Joseph is described as “a righteous man”(Mt1:19) and an angel greets him in a dream “Joseph, son of David” (Mt 1:20).  This description highlights his ancestry and his commitment to the Law given to his people by the Lord God.  Thus, we have two individuals committed to their God and to their shared heritage.

As Joseph strove to provide for and protect his family in their Egyptian displacement, we can imagine him taking comfort in the words that his Bible offered.  Psalm 137 could have particular meaning for Mary and him as they thought about the history of their nation.  At the heart of this memory is the realization that the Lord brings his people home.  That knowledge gave strength and power to the waiting, joined with a resolve never to forget God’s presence among God’s faithful people.