This is NOT a Christian greeting.
It is a Jewish greeting.
You say it is about rest and peace.
Isn't that Christian?
Not exclusively.
You know what is Christian?
Christ is my rest and my peace.
You see, we are to overtly testify of Jesus Christ - not just His benefits.
It is not Christian to praise God. Why not?
Because there are many gods who can intercept that praise.
We are to praise the Lord Jesus Christ.
In order for the Gospel to go forth transforming lives, every truth of it must be packaged In Christ Jesus.
It is the Gospel Of Jesus Christ - not just Good News.
Jesus is our Sabbath.
Jesus is our peace.
The Jews do not have and cannot have real peace without receiving Christ Jesus.
The Jew do not have and cannot have real rest without receiving Christ Jesus.
For Christians to use a Jewish greeting pretending that we share the same rest and peace is an abomination, serving only to encourage Jews in their rejection of Christ Jesus.
Stop it.