The last supper is the night Messiah was betrayed, at the end of the 13th and the beginning of the 14th. He was placed on the tree at 9:00 a.m. on the daylight portion of the 14th and died at 3:00 p.m. on the daylight portion of the 14th, at the same time the Passover lambs were being slaughtered. At the end of the 14th, i.e. sunset, is when the Israelites went to their homes and were admonished not to leave until morning.
Messiah
Exo 12: v22. And ye shall take a bunch of hyssop, and dip [it] in the blood that [is] in the bason, and strike the lintel and the two side posts with the blood that [is] in the bason; and none of you shall go out at the door of his house until the morning.
How can we prove that the last supper is not the first day of the feast of unleavened bread using scriptures? Much confusion abounds due to inaccurate translations.
Exodus, chapter 12, shows that the lamb was set aside on the 10th day, fed water and then killed on the day portion of the 14th. At the same time, the blood was placed on the door, the Israelites were admonished to stay in their homes until morning. Some have difficulty with verse six where it says to kill the lamb in the evening. In Hebrew, between the evenings actually means from high noon to when the sun is going down. The Passover is the preparation day where the 1-year-old lamb without blemish is slaughtered at 3:00 p.m. Notice verse 15 and verse 18 which says to eat unleavened bread for 7 days from the 14th through the 21st. If you eat unleavened bread from the start of the 14th through the 21st that would be 8 days, therefore clearly the scriptures are saying at the end of the 14th, i.e. the 15th, the first day of the feast of unleavened bread is when you start eating unleavened bread.
Did our Creator sin when he had the last supper and left the house before morning when he went to the garden of Gethsemane? Yahweh forbid! The last supper was at the sunset, or end of the 13th and the beginning of the 14th. Days begin at sunset and end at the following sunset.
Genesis 1:16 The sun rules the day and the moon the lesser light rules the night.
Leviticus 23:32 proves a day lasts from even to even, i.e., sunset to sunset. Thus, when the sun (which rules the day) falls below the horizon at sunset the new day has begun.
The last supper was with leavend bread and new wine (unfermented grape juice) after sunset on the 13th (beginning of the 14th). The feast of unleavened bread Day 1 was on the 15th after sunset and was with unleavened bread and old wine (fermented grape juice). The preparation day or Passover was not a high holy day however, the 15th or feast of unleavened bread day one is a high holiday requiring a holy convocation.
The Father and Son planned his perfect sacrifice to absorb all sin (past present and future). I believe the preparation day, while not a high holy day, is beyond an annual High Holy day in its significance. It's the greatest event of all time which guarantees every bit of creation an endless life in in the new heavens and earth. Our Creator asked us to keep the last supper in remembrance of him. The leavened bread signifies a portIon of his own spiritual body (assembly) and the juice his spiritual blood (Holy Spirit or Spirit of Messiah).
The last supper looks forward to Pentecost when the disciples would receive the Holy Spirit and be part of the first fruits.
Luk 24: v49. And, behold, I send the promise of my Father upon you: but tarry ye in the city of Jerusalem, until ye be endued with power from on high.
Leviticus 23:17 mentions two wave loaves baked with leaven and are called first fruits. It also looks forward to the two witnesses which are part of the 144,000, likely the first two to be resurrected at the seventh trumpet. See Rev. 11:11-12.
After being baptized and having hands laid on you, you are begotten and receive a down payment of the spirit of Messiah. In this life you're in the spiritual womb, so to speak . As you overcome, the spirit of Messiah matures in you .
Gal 4: v19. My little children, of whom I travail in birth again until Messiah be formed in you.
Revelation, chapters 1-3, emphasizes the importance of repentance and overcoming to the 7 assemblies (the small flocks or assemblies being perfected). If fully formed by the time of the seventh trumpet you truly will be “born again” into a spiritual body and be with our Creator eternally.
For more information on Passover read the beautiful articles by Bob Bondurant April 16, 2019, December 19, 2019, January 18, December 4,2018, and December 5,2015.