What does Luke 1:11 mean?

In the temple, as God had instructed for the tabernacle, there were two partitioned areas covered by curtains. The innermost room was the Most Holy Place, where the ark of the covenant was kept. The area just outside this was the Holy Place, in which was an altar specifically designed for burning incense (Exodus 30:1–8; 40:26–27). Twice a day, a priest would offer incense there. In the New Testament era, it seems the honor of performing this rite was assigned by chance (Luke 1:8–9). The person chosen in this instance is Zechariah, an honorable priest who has never had children (Luke 1:5–7).

Because of the temple's layout, Zechariah would be alone between the two sets of curtains, while the other worshippers were in the courtyard. Only he would see this angelic visitor. Zechariah's experience is not a hallucination or fantasy. He is lucid enough to see the angel standing in a specific location. The conversation is clear, and the angel's instructions will be understood. The news is wonderful: after reminding the priest not to be afraid (Luke 1:12), the angel predicts that Zechariah and Elizabeth will finally have a child (Luke 1:13).