Luke 1:8

Now while he was doing priestly duty before God in the prescribed course of his class,

Luke 1:5

There was in the time of Herod, the king of Judaea, a priest of the name of Zechariah, belonging to the class of Abijah. He had a wife who was a descendant of Aaron, and her name was Elizabeth.

Treasury of Scripture Knowledge

Summary

And it came to pass, that while he executed the priest's office before God in the order of his course,

Bible References

In

Luke 1:5
There was in the time of Herod, the king of Judaea, a priest of the name of Zechariah, belonging to the class of Abijah. He had a wife who was a descendant of Aaron, and her name was Elizabeth.