“On the fourteenth day of the first month at twilight is the Lord’s Passover.”
-Leviticus 23:5 (New KJV)
On the 14th of NISSAN in the evening just BEFORE the land is submerged in darkness, the Passover Lamb is to be slaughtered.
Remember that a Hebrew day BEGINS when the sun sets (not in the morning when the sun rises).
This makes perfect sense, because if the lamb was slaughtered after sundown, it would have been the 15th day of NISSAN instead of the 14th day of NISSAN, which would have been contrary to the Biblical instruction.
Now we don’t have to guess at any of this.
Let’s just take a look at the original Hebrew words for “at twilight”.
It says BEIN HA-‘ARBAYIM.
This phrase definitely means sometime after the mid-day (around noon-ish) and BEFORE darkness sets in.
Passover is really just a one day event.
It’s a ONE DAY Biblical Feast on the 14th of NISSAN.
Recall that Passover commemorates that terrifying (for God’s enemies) and wonderful (for God’s Chosen) evening when the Lord killed all the firstborn of Egypt.
This killing included both people and livestock.
The Israelites were instructed to slaughter a lamb and paint it’s blood on the doorposts of their homes.
When the Angel of the Lord saw the blood, He was not allowed to pass through the door to enter the house.
Incidentally, the word PESACH does NOT mean “passover“, but that’s a separate discussion we’ll get into later.
Well, after that night, we all know what happened next.
Pharaoh finally did let Israel go and thus Israel began their exodus.
Finally, understand that Passover is NOT connected to a certain day of the week.
In other words, every year what day the 14th of NISSAN falls on changes.
It’s just like our secular New Year’s day.
Every year, January 1st falls on a different day.