Luke 1:10
And when the time for the burning of incense came, all the assembled worshipers were praying outside — the congregation praying outside while the priest offers incense inside is the liturgical structure of the daily offering. The prayers of the congregation and the incense rising together communicate the intercessory character of the temple worship. The outside/inside distinction sets up the private nature of Zechariah's encounter: the congregation prays; the priest enters; the angel appears where only the priest can see.