Matthew Poole and continuators on Exodus 12:4

4 And if the houshold 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.

(i. e) For the eating of the whole lamb at one meal, according to the rule, ver. 8, 10. If the persons be so few that they cannot eat it up without gluttony.

Or rather thus, word for word, And, or Then he (the master of that Family) shall take also his neighbour next unto his house, he shall take him and his family into society with himself, they shall joyn together.

Or, persons, i. e. as the two families shall consist of more or fewer persons. I suppose, the meaning is, that if his next neighbours family were of it self sufficient for the eating of the whole lamb, that he should pass over that to the next small family, which being joyned with his might make up a fit number, which, as the Hebrew Doctours tell us, was ten, besides women and children.

(i. e) According to the proportion which he can or commonly doth eat. The meaning is this, The whole lamb being to be eaten at once, and a sufficient number being necessary to that end, and there being great variety in mens stomachs and meals, they were to give allowance for that, and to take either more or fewer persons, as their stomachs were better or worse.