What does Luke 2:4 mean?
Joseph is engaged to Mary (Luke 1:26–27), who is expecting a child conceived by the Holy Spirit (Luke 1:30–33). They are travelling due to a government-ordered census (Luke 2:1–2). In this case, the census required people go to their ancestral hometowns (Luke 2:3). Jesus will be born here, fulfilling prophecy (Luke 2:6).Later, Luke will explain Jesus' genealogy. The later reference to Joseph as the "son of Heli" likely means son-in-law (Luke 3:23), meaning Luke's list seems to run the family line through Mary. This establishes Jesus as a biological member of David's line. As Jesus' earthly, adoptive father, Joseph would legally bring Jesus into the family line of David. Matthew's tracing of Joseph's genealogy confirms those details (Matthew 1:1–17).
Luke 2:1–7 gives a brief explanation of Jesus' unusual birth. Some traditional details of this event are just that: traditional, and not necessarily given in Scripture itself. Luke establishes a historical timeframe, when Joseph and Mary travel to Bethlehem to participate in a taxed census. Due to the number of travelers, lodgings are crowded. Mary gives birth and lays Jesus in an animal's feeding trough.
The early part of this chapter is famously read at Christmas, while celebrating the birth of Jesus. Luke gives a relatively brief description of how Mary came to give birth in a stable, laying Jesus in a feeding trough. Nearby shepherds are informed of the news by multiple angels. Two people speak in praise of God at Jesus' circumcision. Years later, Joseph and Mary lose track of Jesus on the way back from Jerusalem, only to find Him astounding teachers in the temple with His wisdom.