Responsorial Psalm (Psalm 147)
R. Blessed are all who wait for the Lord.
 The LORD rebuilds Jerusalem;
 and gathers the dispersed of Israel. 
R. Blessed are all who wait for the Lord.
 The Lord heals the brokenhearted
 and binds up their wounds.
 The Lord tells the number of the stars;
 and calls each by name. R. Blessed are all who wait for the Lord.
https://bible.usccb.org/bible/readings/120421.cfm
Patience is the key virtue of Advent, to wait for the Lord. The image of Mary, Great with Child, captures the imagination of the church during this Holy Season.