This Bible 911 is from Numbers and is about the second Passover the Israelites were to celebrate in the Exodus. Our verse shows how important it was to God that all of His children remember their personal and corporate exodus out of Egypt. A problem had come up because some of the people were unclean during the first month and could not join the community in the observance. Exodus 12 has the story and the rules for the very first Passover.
11 The fourteenth day of the second month at even they shall keep it, and eat it with unleavened bread and bitter herbs. (KJV) bold added
If you missed the first month you had to observe Passover during the second month of the year. The rules were the same; verse twelve stresses not leaving any of the lamb until morning, and breaking no bones of the lamb. The lamb was killed on the fourteenth and eaten overnight on the fifteenth. Remember their day starts in the evening.
Jesus was our Passover Lamb and He was killed before twilight and buried before the morning. His legs were not broken because He was already dead. All of this was not wasted on the centurion, that is why he said that Jesus was the Son of God (Matthew 27:54).
Extra: I have no doubt that Passover was celebrated it just is not mentioned that often in Scripture. Find all the times it is recorded that Passover was observed.