Charles Spurgeon Commentary Exodus 12:3-4

"Speak ye unto all the congregation of Israel, saying, In the tenth [day] of this month they shall take to them every man a lamb, according to their fathers` houses, a lamb for a household: and if the household be too little for a lamb, then shall he and his neighbor next unto his house take one according to the number of the souls; according to every man`s eating ye shall make your count for the lamb." — Exodus 12:3-4 (ASV)

Speak to all the congregation of Israel, saying, In the tenth day of this month they shall take to them every man a lamb, according to the house of their fathers, a lamb for a household: and if the household be too little for the lamb, let him and his neighbor next to his house take it according to the number of the souls; every man according to his eating shall make your count for the lamb.

The worship of God must be rendered in an orderly manner, with proper thoughtfulness and preparation. This paschal supper was not to be celebrated in any way that the people might choose; but they were to take time to have the lamb properly examined, so that it would be found perfect in every respect, and that everything would be set in order so that the feast would be observed with proper reverence and solemnity.

Let us take care that we act this way in all our devotions; let us never rush to prayer or hurry to praise; but let us pause for a while and think about what we are about to do, lest we offer the sacrifice of fools, and so cause the Lord to tell us to take back what we have brought to put on His altar without proper thoughtfulness.

Speak ye unto all the congregation of Israel, saying, In the tenth day of this month they shall take to them every man a lamb, according to the house of their fathers, a lamb for a house: and if the household be too little for the lamb, let him and his neighbour next unto his house take it according to the number of the souls; every man according to his eating shall make your count for the lamb.

The separation of the lamb was to take place some four days before the time of its slaughter. Probably it was kept in the house; according to Jewish tradition, this was so, and the household would hear it bleating and be reminded of the purpose for which it was to be slain.