THE FIRST PASSOVER KEPT.
(21) Moses called for all the elders. — He had been directed to “speak unto all the congregation” (Exodus 12:3), but understood the direction as allowing him to do so mediately, through the elders.
Draw out. — Some understand this intransitively — “Withdraw, and take,” i.e., go, and take; others transitively — “Withdraw a lamb from the flock.”
According to your families — i.e., with reference to the number of your families, but not necessarily one for each. (See Exodus 12:4.)