Albert Barnes Commentary Leviticus 23:37-38

"These are the set feasts of Jehovah, which ye shall proclaim to be holy convocations, to offer an offering made by fire unto Jehovah, a burnt-offering, and a meal-offering, a sacrifice, and drink-offerings, each on its own day; besides the sabbaths of Jehovah, and besides your gifts, and besides all your vows, and besides all your freewill-offerings, which ye give unto Jehovah." — Leviticus 23:37-38 (ASV)

The meaning appears to be: “these are the yearly appointed times on which you shall hold holy convocations and offer to Yahweh sacrifices, in addition to the Sabbath offerings (Numbers 28:9–10) and to all your voluntary offerings.” Compare Numbers 29:39.