The Sabbath was made for mankind - "and rested the seventh day therefore God Blessed THE Sabbath day and made it holy" -- however the "Sabbaths" of Lev 23 as annual holidays are for the Jews as Paul points out in Acts 21 while observing the ceremonial law.
Where did you lift the above quote from?
In any case - whoever said that the "mankind does not include the Jews"??
Who is trying to make such a foolish argument?
Really? who else has posted such a notion?
Is 56
For thus says the Lord:
To the eunuchs who keep My Sabbaths,
And choose what pleases Me,
And hold fast My covenant,
5 Even to them I will give in My house
And within My walls a place and a name
Better than that of sons and daughters;
I will give them an everlasting name
That shall not be cut off. 6 Also the sons of the foreigner
Who join themselves to the Lord, to serve Him,
And to love the name of the Lord, to be His servants
Everyone who keeps from defiling the Sabbath,
And holds fast My covenant
7 Even them I will bring to My holy mountain,
And make them joyful in My house of prayer.
Their burnt offerings and their sacrifices
Will be accepted on My altar;
For My house shall be called a house of prayer for all nations.
Seven is your unlucky number.
Who is the everyone since you highlighted it? You cling to the law (old covenant) and refuse to accept the New Covenant.
3 Neither let the son of the stranger, that hath joined himself to the Lord, speak, saying, The Lord hath utterly separated me from his people: neither let the eunuch say, Behold, I am a dry tree.
4 For thus saith the Lord unto the eunuchs that keep my sabbaths, and choose the things that please me, and take hold of my covenant;
5 Even unto them will I give in mine house and within my walls a place and a name better than of sons and of daughters: I will give them an everlasting name, that shall not be cut off.
6 Also the sons of the stranger, that join themselves to the Lord, to serve him, and to love the name of the Lord, to be his servants, every one that keepeth the sabbath from polluting it, and taketh hold of my covenant;
How does one join themselves to that covenant? Are they then strangers to it?
Rhetorical question answered with -
48 And when a stranger shall sojourn with thee, and will keep the passover to the Lord, let all his males be circumcised, and then let him come near and keep it;
and he shall be as one that is born in the land: for no uncircumcised person shall eat thereof. Ex 12
This show they're no longer a stranger.