All keep the Sabbath

Isaiah 56:2 Blessed is the man who does this, and the son of man who becomes strong in it (hangs on to it), guarding the Sabbath lest he profane it (polluting or render it ceremonially or ritually making it common), and guarding his hand from doing any evil. 

Isaiah 56:3, "And let not the son of the foreigner (other nation - not native to Israel) who has joined himself to Yahuah speak, saying, Yahuah has certainly separated me from His people,'.....

Isaiah 56:6, "Also the sons of the foreigner who join themselves to Yahuah, to serve Him, and to love the Name of Yahuah, to be His servants, all who guard the Sabbath, and not profane it, and are holding onto My covenant - them I shall bring to My set-apart mountain, and let them rejoice in My house of prayer.

Any foreigner (stranger) who loves Yahuah and keeps His commands, including the Sabbath, they are accepted and become part of the covenant that Yahuah made with Abraham, Isaac and Jacob.

Yahuah says in verse 5, to them I shall give in My house and within My walls a place and a name better than that of sons and daughters - I give them an everlasting name that is not cut off.

Anyone has the opportunity to be in Yahuah's covenant!

This is what Yahuah says to those who turned away from the Sabbath; "If you do turn back your foot from the Sabbath, from doing your pleasure on My set-apart day, and shall call the Sabbath 'a delight,' the set-apart day of Yahuah 'esteemed,' and shall respect it, not doing your own ways, nor finding your own pleasure, nor speaking your own words, then you shall delight yourself in Yahuah. And I shall cause you to ride on the heights of the earth, and feed you with the inheritance of Jacob your father. For the mouth of Yahuah has spoken!" - Isaiah 58:13-14.

The Sabbath is a very important sign!

Not much I can add as the prophet said it well and hopefully, we will hear.