Jesus had already predicted His death to his disciples and also told them that He will be raised from the dead on the third day.  The Passover was a once a year festival for the Jews to remember what God had done for them during the Egyptian era.  During Jesus's ministry, He spread the good news to all that whoever believe in HIM will receive the living water.  Therefore, as God's Will, Jesus knew that He had to be sacrified for all of us sinners bearing our sins and shame so that we may have a relationship direct with God and through Him we receive His amazing grace. Jesus new coveneant supersedes all animal sacrifices for sins committed because He is the Worthy Lamb sacrified to God once and for all for we sinners. Therefore, we remembered His coveneant whenever we partake in the weekly Holy Communion.