Partake

To the Protestant, if you would understand the Eucharist, you must start at the Passover.  Was it sufficient for the Israelites to sacrifice a lamb, to coat their lintels with its blood alone?  Or was it also necessary, even commanded, that they partake of the passover sacrifice by eating the lamb without blemish?  If so, woe unto you who deny the Body of the Lord in the Mass, for how can you partake in His sacrifice if you do not partake in His Body and Blood?