Thou shalt therefore sacrifice the passover unto the LORD thy God, of the flock and the herd, in the place which the LORD shall choose to place his name there.
Thou shalt ... sacrifice the Passover, х Pecach (H6453) ... tso'n (H6629) uwbaaqaar (H1241); Septuagint, thuseis to pascha kurioo too Theoo sou probata kai boas]. The reference is not to the paschal lamb, which was strictly and properly the Passover. The whole solemnity is here meant, as is evident from the mention of the chazizah, the additional victims, peace offerings, that were presented by private individuals on the subsequent days of the feast (Numbers 28:18-19; 2 Chronicles 35:7-9), and from the allusion to the continued use of unleavened bread for seven days, whereas the Passover itself was to be eaten at once.
The words before us are equivalent to 'Thou shalt observe the feast of the Passover' - i:e., the whole festival of seven days (cf. Ezekiel 45:21), including, along with the public sacrifices for every day, the voluntary oblations of individuals. The early Rabbis interpreted "the flock" as referring to the paschal victims, and "the herd" to the chazizah.