Acts 5:29, "And Kĕpha and the other emissaries answering, said, “We have to obey YHWH rather than men.”
The Sabbath is the 7th day, those claims that we don't know what day are gross denial of Scripture:
[FONT=Times New Roman, serif]Genesis/Bereshith (the beginning)[/FONT]
[FONT=Times New Roman, serif]1:5, "And Elohim called the light ‘day’ and the darkness He called ‘night.’ And there came to be evening and there came to be morning, one day."[/FONT]
[FONT=Times New Roman, serif]1:8, "And Elohim called the expanse ‘heavens.’ And there came to be evening and there came to be morning, the second day."[/FONT]
[FONT=Times New Roman, serif]1:13, "And there came to be evening and there came to be morning, the third day."[/FONT]
[FONT=Times New Roman, serif]1:19, "And there came to be evening and there came to be morning, the fourth day."[/FONT]
[FONT=Times New Roman, serif]1:23, "And there came to be evening and there came to be morning, the fifth day."[/FONT]
[FONT=Times New Roman, serif]1:31, "And Elohim saw all that He had made, and see, it was very good. And there came to be evening and there came to be morning, the sixth day."[/FONT]
[FONT=Times New Roman, serif]2:3, "And Elohim blessed the seventh day and set it apart, because on it He rested from all His work which Elohim in creating had made."[/FONT]
The Sabbath was always for Hebrew and Gentile alike:
[FONT=Times New Roman, serif]Isaiah 56:1-7, “Thus said יהוה[FONT=Times New Roman, serif], “Guard right-ruling, and do righteousness, for near is My deliverance to come, and My righteousness to be revealed. Blessed is the man who does this, and the son of man who becomes strong in it, guarding the Sabbath lest he profane it, and guarding his hand from doing any evil. And let not the son of the gentile who has joined himself to [/FONT][/FONT][FONT=Times New Roman, serif]יהוה [FONT=Times New Roman, serif]speak, saying, ‘[/FONT][FONT=Times New Roman, serif]יהוה [/FONT][FONT=Times New Roman, serif]has certainly separated me from His people,’ nor let the eunuch say, ‘Look I am a dry tree.’ For thus said [/FONT][/FONT][FONT=Times New Roman, serif]יהוה[FONT=Times New Roman, serif], “To the eunuchs who guard My Sabbaths, and have chosen what pleases Me, and are holding onto My covenant: 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. Also the sons of the gentile who join themselves to [/FONT][/FONT][FONT=Times New Roman, serif]יהוה[/FONT][FONT=Times New Roman, serif], to serve Him, and to love the Name of [FONT=Times New Roman, serif]יהוה[/FONT][FONT=Times New Roman, serif], 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. Their ascending offerings and their sacrifices are accepted on My altar, for My house is called a house of prayer for all the peoples.”[/FONT][/FONT]
It will not pass:
[FONT=Times New Roman, serif]Mat 5:18, "I say to you; Unless heaven and earth passes away, one yodh; the smallest of the letters will in no way pass from the Law, until all things are perfected."
Revelation 21:1, "I saw a new heaven and a new earth, for the first heaven and the first earth had passed away." [/FONT]
Not even in the New Kingdom:
[FONT=Times New Roman, serif]Isayah 66:21-24, “And from them too I shall take for priests – for Lĕwites,” declares יהוה[/FONT][FONT=Times New Roman, serif]. For as the [/FONT][FONT=Times New Roman, serif]new heavens and the new earth that I make stand before Me,” declares [/FONT][FONT=Times New Roman, serif]יהוה[/FONT][FONT=Times New Roman, serif], “so your seed and your name shall stand[/FONT][FONT=Times New Roman, serif]. And it shall be that from New moon to New moon, and from Sabbath to Sabbath, all flesh shall come to worship before Me,” declares [/FONT][FONT=Times New Roman, serif]יהוה[/FONT][FONT=Times New Roman, serif]. And they shall go forth and look upon the corpses of the men who have transgressed against Me. For their worm shall not die, and their fire not be quenched. And they shall be repulsive to all flesh!” [/FONT]
Evil powers try to change it in peoples minds:
[FONT=Times New Roman, serif]Daniel 7:25, “And he shall speak great words against the most High, and shall wear out the saints of the Most High, and think to change times and laws: and they shall be given into his hand [/FONT] ..."