The Passover was an observance required by the Covenant which God made with Israel at Sinai when Moses brought the people out of Egypt.
There is no instruction given concerning washing.
The prohibition is that of eating leavened bread.
Jesus Christ fulfilled the Old Covenant and instituted a New Covenant as prophesied by Jeremiah.
Jeremiah 31:31 Behold, the days come, saith the LORD, that I will make a new covenant with the house of Israel, and with the house of Judah: 32 Not according to the covenant that I made with their fathers in the day that I took them by the hand to bring them out of the land of Egypt; which my covenant they brake, although I was an husband unto them, saith the LORD: 33 But this shall be the covenant that I will make with the house of Israel; After those days, saith the LORD, I will put my law in their inward parts, and write it in their hearts; and will be their God, and they shall be my people.
Hebrews 8:8 For finding fault with them, he saith, Behold, the days come, saith the Lord, when I will make a new covenant with the house of Israel and with the house of Judah:
The New Covenant replaces the Old
Hebrews 8:13 In that he saith, A new covenant, he hath made the first old. Now that which decayeth and waxeth old is ready to vanish away.
Jesus Christ is the mediator of the New Covenant which he ratified in his own blood.
Hebrews 12:24 And to Jesus the mediator of the new covenant, and to the blood of sprinkling, that speaketh better things than that of Abel.
The only ordinance instituted by Jesus Christ under the New Covenant is that of meeting often with fellow believers to share bread and wine in remembrance of his sacrifice.
1 Corinthians 11:23 For I have received of the Lord that which also I delivered unto you, That the Lord Jesus the same night in which he was betrayed took bread: 24 And when he had given thanks, he brake it, and said, Take, eat: this is my body, which is broken for you: this do in remembrance of me. 25 After the same manner also he took the cup, when he had supped, saying, This cup is the new testament (Covenant) in my blood: this do ye, as oft as ye drink it, in remembrance of me. 26 For as often as ye eat this bread, and drink this cup, ye do shew the Lord’s death till he come.
This ordinance is generally observed on the first day of each week.
Those who believe the gospel and are baptised into Christ have no reason to observe the Passover.
I hope you find this helpful.
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