'Festivals' in the Bible

"Speak to the {Israelites}, and say to them, 'The festivals of Yahweh that you shall proclaim [are] holy assemblies; these [are] my appointed times.

" 'These [are] Yahweh's festivals, which you must proclaim, holy assemblies to present an offering made by fire to Yahweh--burnt offering and grain offering, sacrifice and libations, {each on its proper day}--