Rashi on Exodus 12:21/רש"י על שמות י״ב:כ״א

1משכו DRAW OUT — He who has sheep let him draw one out from his own,

2וקחו OR TAKE, and he who has no sheep let him purchase one in the market (Mekhilta).

3למשפחתיכם [A LAMB] ACCORDING TO YOUR FAMILIES — this corresponds to שה לבית אבות a lamb for the house of their fathers in verse 3.