There are some historical difficulties with precisely identifying Jesus’ last meal with the regular Passover. (14:12 seems to be at odds with the notice in 14:2 which says that the Jewish leaders wanted to arrest Jesus before the Passover season.) Whatever the specific day, it does seem clear that in the upper room the disciples were ready to celebrate the family Passover, perhaps as an antedated service, prior to the regular feast. The Jewish Passover
Mark 14:12–25