YHWH set apart/made holy the 7th day Sabbath and the Feast Days:
Genesis 2:1-3, “Thus the heavens and the earth were completed, and all their array. And in the seventh day the Mighty One completed His work which He had done, and He rested on the seventh day from all His work which He had made. And the Mighty One blessed the seventh day and set it apart, because on it He rested from all His work which the Mighty One in creating had made.
Psalm 104:19, "You appointed the moon for setting the appointed times*. The sun knows its going down."
“appointed times”is word #H4150 - Original Word: מוֹעֵד, Part of Speech: Noun Masculine, Transliteration: moed, Phonetic Spelling: (mo-ade'), Short Definition: meeting, Word Origin from yaad, Definition - appointed time, place, or meeting
Leviticus 23:2-4, “Speak to the children of Yisra’ĕl, and say to them, ‘The appointed times (#H4150) of יהוה, which you are to proclaim as set-apart (#H6944) gatherings (#H4744), My appointed times (#H4150), are these: Six days work is done, but the seventh day is a Sabbath (#H7676) of rest (#H7677), a set-apart (#H6944) gathering (#H4744). You do no work, it is a Sabbath to יהוה in all your dwellings. These are the appointed times (#H4150) of יהוה, set-apart (#H6944) gatherings (#H4744) which you are to proclaim at their appointed times (#H4150)."
"appointed times" is word #H4150 מוֹעֵד mow`ed (mo-ade') n-m. 1. (properly) an appointment, i.e. a fixed time or season., 2. (specifically) a festival., 3. (conventionally) a year., 4. (by implication) an assembly (as convened for a definite purpose)., 5. (technically) the congregation., 6. (by extension) the place of meeting., 7. (also) a signal (as appointed beforehand)., [from H3259], KJV: appointed (sign, time), (place of, solemn) assembly, congregation, (set, solemn) feast, (appointed, due) season, solemn(-ity), synogogue, (set) time (appointed). , Root(s): H3259
"set-apart" is word #H6944 קֹדֶשׁ qodesh (ko'-desh) n-m. 1. a holy thing., 2. (of location) a holy place., 3. (of event) a holy event (i.e. a memorial)., 4. (abstract, rarely) holiness., 5. (double emphasized) Holy of Holies (the holy place of holy places, the most holiest place)., 6. Holy (Spirit)., [from H6942]
KJV: consecrated (thing), dedicated (thing), hallowed (thing), holiness, (X most) holy (X day, portion, thing), saint, sanctuary. , Root(s): H6942 , See also: H4720, G39
Let us not foget these are not "Jewish day" but for all Israyl, and those in Messiah ARE Israyl:
Romans 9:6-8, "However, it is not as though YHWH's plan had failed. For it is not everyone who is a descendant of Yisra’yl who belongs to Yisra’yl. Nor, just because they are his descendants, are they all Abraham's children; but: In Isaac will your seed be called. That is, it is not those who are the children of the flesh who are YHWH's children; but it is the children of the promise who are regarded as Abraham's seed."
Psalm 105:6-9, "O seed of Abraham His servant, You children of Yaaqob, His chosen ones! He is YHWH our Father! His judgments are in all the earth. He has remembered His covenant forever, the Law He commanded for a thousand generations; Which He made; ratified, established, with Abraham, and vowed by His oath to Isaac. He confirmed it; let it stand, to Yaaqob for a Law, and to Israyl for an everlasting covenant."
Leviticus 23
1, And יהוה spoke to Mosheh, saying,
2, “Speak to the children of Yisra’yl, and say to them, ‘The appointed times of יהוה, which you are to proclaim as set-apart gatherings, My appointed times, are these:
Seventh Day Sabbath:
Leviticus 23:3, ‘Six days work is done, but the seventh day is a Sabbath of rest, a set-apart gathering. You do no work, it is a Sabbath to יהוה in all your dwellings.
High Sabbaths:
Leviticus 23:4, ‘These are the appointed times of יהוה, set-apart gatherings which you are to proclaim at their appointed times.
Passover:
Leviticus 23:5, ‘In the first new moon, on the fourteenth day of the new moon, between the evenings, is the Pĕsaḥa to יהוה.
Unleavened Bread/Firstfruits:
Leviticus 23:6, ‘And on the fifteenth day of this new moon is the Festival of Matzotb to יהוה – seven days you eat unleavened bread.
Feast of Weeks:
Leviticus 23:15, ‘And from the morrow after the Sabbath, from the day that you brought the sheaf of the wave offering, you shall count for yourselves: seven completed Sabbaths.
16, ‘Until the morrow after the seventh Sabbath you count fifty days, then you shall bring a new grain offering to יהוה.
Feast of Trumpets:
Leviticus 23:23, And יהוה spoke to Mosheh, saying,
24, “Speak to the children of Yisra’yl, saying, ‘In the seventh new moon, on the first day of the new moon, you have a rest, a remembrance of Teru‛ah, a set-apart gathering.
Day of Atonement:
Leviticus 23:26, And יהוה spoke to Mosheh, saying,
27, “On the tenth day of this seventh new moon is Yom haKippurim. It shall be a set-apart gathering for you.
Feast of Tabernacles and The Last Geart Day/Feast of YHWH:
Leviticus 23:33, And יהוה spoke to Mosheh, saying,
34, “Speak to the children of Yisra’yl, saying, ‘On the fifteenth day of this seventh new moon is the Festival of Sukkot for seven days to יהוה.
35, ‘On the first day is a set-apart gathering, you do no servile work.
36, ‘For seven days you bring an offering made by fire to יהוה. On the eighth day there shall be a set-apart gathering for you, and you shall bring an offering made by fire to יהוה. It is a closing festival, you do no servile work.
37, ‘These are the appointed times of יהוה which you proclaim as set-apart gatherings, to bring an offering made by fire to יהוה, an ascending offering and a grain offering, a slaughtering and drink offerings, as commanded for every day –
38, besides the Sabbaths of יהוה, and besides your gifts, and besides all your vows, and besides all your voluntary offerings which you give to יהוה.
39, ‘On the fifteenth day of the seventh new moon, when you gather in the fruit of the land, celebrate the festival of יהוה for seven days. On the first day is a rest, and on the eighth day a rest.