Leviticus 23:38

Beside the sabbaths of the Lord
The seventh day sabbaths, which were of his appointing, and sacred to his service and worship; on which, when any of the feasts fell, it did not hinder the observance of them, or the offering of the several sacrifices on them; nor were those of the sabbath to be omitted on the account of them:

and beside your gifts;
either of the whole congregation, or of a private person, which they thought well to give of their own good will on these festivals, over and above the sacrifices enjoined:

and beside all your vows, and beside all your freewill offerings, which
ye give unto the Lord;
which seem to explain what is meant before by gifts.