Why do the followers of Reformed Samaritanism use the phrase “peace be upon him” when mentioning the name of a deceased person, just as Muslim believers usually do?

Every Muslim and Christian should know this: “Jews and Samaritans can be right with God [having the right theology]; but so can be Muslims and Christians [having the right heart for God]"

According to Moses Law, as soon as a person dies, he becomes impure. Why? Because the Law states that all human corpses are ritually unfit [due to the decaying fecal matter located inside of it]. Also, anyone who touches a dead body (like soldiers and executioners) becomes impure for seven days («He that toucheth the dead body of any man, shall be unclean even seven days….. He shall purify himself therewith the third day, and the seventh day he shall be clean... ”- Numbers 19: 11-12 (1599 Geneva Bible)».
In addition, if an unclean person touches a clean person, the latter becomes unclean (“Anything the unclean person touches will become unclean... ”- Numbers 19: 22, Christian standard Bible). And this is why Jews [especially the High priest] wouldn’t come close to a Roman soldier on Passover’s eve, as any acquired impurity would render him unable to eat [or even participate of] the Passover’s lamb.
As is written: “But there were some men who were unclean because of a human corpse, so they could not observe the Passover on that day”- Numbers 9: 6 (Christian standard Bible). And also in another place, “Then they (the Jews) led Jesus from Caiaphas to the [Roman] governor’s headquarters... They did not enter the headquarters themselves; otherwise they would be defiled and unable to eat the Passover”- John 18: 28 (C. S. B. ).
And the former hints at the reason why observant Jews (and Samaritans) had such a hard time believing Jesus was both God, as well as God’s own Passover lamb. They reason with themselves, «How could Jesus be God? Wasn’t Jesus rendered impure by the spat thrown upon his face by a defiled Roman Soldiers? Wasn’t he rendered impure by the touch of the Roman soldier who slapped his face? Didn’t Jesus become impure when becoming a corpse hanging on the cross? How could the absolutely pure God ever become impure?
In fact, if Jesus was God’s own lamb, then the lamb became impure [by it’s prior contact with defiled Roman soldiers], and was therefore no longer fit to be offered as Passover sacrifice. And, even if God had somehow chosen to become impure [by coming in contact with His own human dead corpse], didn’t the Law demand that such an impure person be cleansed on the third and seventh day (being sprinkled with water mixed with the red heifer ashes)? Was Jesus sprinkled twice [after his resurrection] with this holy water?
And, if he wasn’t, isn’t he supposed to be cut off from God’s congregation? As is written: “But a person who is unclean and does not purify himself, that person will be cut off from the assembly, because he has defiled the sanctuary of the Lord. The water for impurity has not been sprinkled on him; he is unclean”- Numbers 19: 20 (C. S. B. ). Besides, Jesus [alleged] resurrection happened on the third day, and by them the Passover sacrifice wasn’t valid anymore, as the lamb could no longer be “eaten” (“You must not leave any of it until morning; any part of it left until morning you must burn”- Exodus 12: 10).
Does the former means that, since they believe in Jesus, both Christians and Muslims practice a false religion? God forbid that we say such a thing! It only means that, the content of the Gospel’s revelation, and the content of Moses revelation (the Torah), aren’t exactly the same. But that doesn’t means that Islam and Christianity aren’t valid religions. Why? Because, even if the above Hebrew theology is absolutely right, and both Christian and Muslim theologies are absolutely wrong, honest and God fearing Muslims and Christians would still be granted God’s personal favor.
Why? Simply because our Creator is Just, as well as merciful. In other words, He judges the intentions of the heart, holding us accountable for the things we do with the portion of truth we know, not for the portion of truth we still don’t know (or yet understand). And the proof? King Abimelech, who showed himself honest and God fearing with the vague [and uncertain] piece of information he knew about Sarah (Abraham’s wife). Abimelech was told that beautiful Sarah was Abraham’s sister, and since no commoner would ever object to becoming the King’s brother in Law, Abimelech went ahead and made Sarah one of his many wives.
Thus, although the wrong piece of information led Abimelech into a questionable path [taking another man’s wife], he still counted with God’s personal favor, as God knew his heart had been honest and faithful to what he considered to be the truth. As is written: «Then God said to him (Abimelech) in the dream, “Yes, I KNOW YOU DID THIS IN THE INTEGRITY OF YOUR HEART, for it was I Who kept you back and spared you from sinning against Me; therefore I did not give you occasion to touch her”»- Genesis 20: 6.
Thus, just like honest and God fearing Abimelech was granted the honour of having direct revelation from the God of Abraham, likewise honest and God fearing Christians and Muslims will be granted the honor of receiving direct revelation from the God of Abraham (guidance, wisdom, prophecy, deliverance, the Holy Spirit, etc).

Why do the followers of Reformed Samaritanism use the phrase “peace be upon him” when mentioning the name of a deceased person, just as Muslim believers usually do?

Why do followers of Reformed Samaritanism use the phrase “peace be upon him” when mentioning the name of a deceased person, just as Muslim believers usually do? The reason why we do it has to do with the fact that since time immemorial Hebrew believers used to follow the same tradition. For example, it is related that Rabbi Elazar of Modi'in used to say: “One who profanes the Kodeshim (sacred material); one who desecrates the holidays; one who whitens (embarrasses) the face of another in public; one who nullifies the covenant of Abraham our father, PEACE BE UPON HIM; one who reveals meanings in the Torah that run contrary to the law, even though he has Torah knowledge and good deeds, he has no share in the world to come” (Pirke Avot 5: 3)