Why Is The Feast Of Unleavened?

I believe that Mark includes so much detail in this passage for a couple different reasons. The first reason is to establish Jesus’ authority as God to be all knowing. The second reason is that by putting in some details about the Feast of Unleavened, this allows people today to understand the realities of the festival and what it entails for those who participate in it.

2. ›› According to Exodus 14:12-25, for the Passover, each Israelite family had to take a lamb on the tenth day of the month. Additionally, the lamb not only had to be males without defect, but they also had to be one year old. On the fourteenth day, after taking care of the lamb, every family in Israel was supposed to kill their lamb at twilight. After this, some of the blood of the lamb was to be put on the top and sides of the families’ doorposts. On the night of the fourteenth day, every family was supposed to eat the lamb with bitter herbs, not boiled or raw, but roasted over a fire and eaten completely, organs, head, and legs included, along with bread without yeast. If there are leftovers, the families had to burn what remained. Additionally, the Israelites had to eat it with their cloaks tucked into their belts, wearing their sandals, and holding their staffs in their hand. Last of all, they had to eat the lamb in haste.
›› The scene appears very much like a routine. Each member of the Israelite families are deeply concentrated and are very focused on preparing the Passover exactly how they are ordered to. When it comes time to actually eat the meal, the family gathers to scarf down all the food they can to put in their part of getting rid of all the food while seriously reflecting on the meaning of the festival they are participating