Leviticus 23:2, My feasts [Heb. moedim]. YHVH calls these feasts his feasts. They’re not men’s feasts or the Jewish feasts! They came from YHVH and belong to him. When men pervert YHVH’s feasts by mixing in pagan traditions, they’re no longer YHVH’s feasts, but men’s feasts (e.g. Isa 1:13–15; Amos 5:21; Hos 2:11). When men pollute his feasts and appointed times, YHVH says that he hates them because they’re no longer his feasts (Isa 1:14–15).
In Ezekiel 20, we see that YHVH’s feasts (or sabbaths) are a covenantal sign between YHVH and his people (Ezek 20:12) that they were to live by (Ezek 20:11), yet which Israel, in rebellion, refused to do while in the wilderness. Instead they defiled his sabbaths by, presumably, not doing them and doing other things on those holy days (Ezek 20:13). Israel’s rebellion against YHVH with regard to their refusal to keep his sabbaths brought upon them YHVH’s judgments (Ezek 20:13). In other words, it was YHVH’s will for the Israelites to keep his sabbaths in the wilderness, but because of their idolatrous rebellion, they refused to do so.
In fact, YHVH calls refusing to observe his sabbaths idolatry and for this sin (along with other sins), the Israelites had to wander in the wilderness for forty years (Ezek 20:15–16). In profaning his sabbaths, YHVH accuses the Israelites of despising his Torah (Ezek 20:16).
YHVH then goes on to urge his people to not follow the example of their rebellious forefathers, but rather to walk in all of his Torah commands (including his sabbaths, Ezek 20:18–20). Because of their profaning his sabbaths, he punished them by scattering them in exile among the heathens. Those modern saints who refuse to keep YHVH’s Sabbath and feasts are walking in the same sin as the ancient Israelites.
Often people who refuse to keep YHVH’s feast days holy do so because the feasts conflict with their secular activities (such as their jobs). YHVH calls this idolatry and being like the heathen (Ezek 20:30, 32).
In the end times, YHVH is going to separate his people out from the heathen and bring them back into covenantal agreement with him including obedience to his sabbaths (Ezek 20:33–38). He will purge from his people those rebels who refuse to obey him including keeping his sabbaths (Ezek 20:38), which are a sign of his covenantal relationship with them.