The difference between Shabbat and Sabbath:
Shabbat is from sunset Friday to sunset Saturday every week. The Sabbaths are all Jewish festivals, as well as the weekly Shabbat.

YaHWeH command us to keep three Holy festivals every year:

Deuteronomy 16:16: ”All your males are to appear three times a year before YaHWeH your God in the place He chooses: at the Festival of Unleavened Bread, the Festival of Weeks, and the Festival of Booths. No one is to appear before YaHWeH empty-handed.”

The Festival of Unleavened Bread (Passover):
Exodus 12:15-20: “Seven days you shall eat unleavened bread. On the first day you shall remove leaven from your houses. For whoever eats leavened bread from the first day until the seventh day, that person shall be cut off from Israel. On the first day there shall be a holy convocation, and on the seventh day there shall be a holy convocation for you. No manner of work shall be done on them; but that which everyone must eat–that only may be prepared by you. So you shall observe the Feast of Unleavened Bread, for on this same day I will have brought your armies out of the land of Egypt. Therefore you shall observe this day throughout your generations as an everlasting ordinance. In the first month, on the fourteenth day of the month at evening, you shall eat unleavened bread, until the twenty-first day of the month at evening. For seven days no leaven shall be found in your houses, since whoever eats what is leavened, that same person shall be cut off from the congregation of Israel, whether he is a stranger or a native of the land. You shall eat nothing leavened; in all your dwellings you shall eat unleavened bread.”

You must therefore observe the Festival of Unleavened Bread in this manner: On the first day, remove all leaven from your house. For seven days, eat unleavened bread. On the first day, there shall be a holy convocation, and on the seventh day, there shall also be a holy convocation for you. No work shall be done on these two days; only what everyone must eat may be prepared by you. Look at the picture below to see when the festival is.

The Festival of Weeks (Shavuot/Pentecost):
Leviticus 23:15-22: “[15] And ye shall count unto you from the morrow after the sabbath, from the day that ye brought the sheaf of the wave offering; seven sabbaths shall be complete: [16] even unto the morrow after the seventh sabbath shall ye number fifty days; and ye shall offer a new meat offering unto YaHWeH. [17] Ye shall bring out of your habitations two wave loaves of two tenth deals: they shall be of fine flour; they shall be baken with leaven; they are the firstfruits unto YaHWeH. [18] And ye shall offer with the bread seven lambs without blemish of the first year, and one young bullock, and two rams: they shall be for a burnt offering unto YaHWeH, with their meat offering, and their drink offerings, even an offering made by fire, of sweet savour unto YaHWeH. [19] Then ye shall sacrifice one kid of the goats for a sin offering, and two lambs of the first year for a sacrifice of peace offerings. [20] And the priest shall wave them with the bread of the firstfruits for a wave offering before YaHWeH, with the two lambs: they shall be holy to YaHWeH for the priest. [21] And ye shall proclaim on the selfsame day, that it may be an holy convocation unto you: ye shall do no servile work therein: it shall be a statute for ever in all your dwellings throughout your generations. [22] And when ye reap the harvest of your land, thou shalt not make clean riddance of the corners of thy field when thou reapest, neither shalt thou gather any gleaning of thy harvest: thou shalt leave them unto the poor, and to the stranger: I am YaHWeH your God.”

You must therefore observe the Festival of Weeks in this manner: It shall be a holy convocation for you, with no servile work therein. There shall be no offerings, for YaHWeH no longer delights in offerings, as written later in this study. Look at the picture below to see when the festival is.

The Festival of Booths (Sukkot): Leviticus 23:39-43: “39 ‘Also on the fifteenth day of the seventh month, when you have gathered in the fruit of the land, you shall keep the feast of YaHWeH for seven days; on the first day there shall be a sabbath-rest, and on the eighth day a sabbath-rest. 40 And you shall take for yourselves on the first day the fruit of beautiful trees, branches of palm trees, the boughs of leafy trees, and willows of the brook; and you shall rejoice before YaHWeH your God for seven days. 41 You shall keep it as a feast to YaHWeH for seven days in the year. It shall be a statute forever in your generations. You shall celebrate it in the seventh month. 42 You shall dwell in booths for seven days. All who are native Israelites shall dwell in booths, 43 that your generations may know that I made the children of Israel dwell in booths when I brought them out of the land of Egypt: I am YaHWeH your God.’ ”

You must therefore observe the Festival of Booths in this manner: On the first day there shall be a sabbath rest, and on the eighth day a sabbath rest, with no work performed on either day. You shall take for yourselves on the first day the fruit of beautiful trees, branches of palm trees, the boughs of leafy trees, and willows of the brook; and you shall rejoice before YaHWeH for seven days. During all seven days, you must dwell in booths.
Look at the picture below to see when the festival is.

We don’t have to make burn offerings to YaHWeH at these feasts any longer because He don’t delight in it any longer.

1 Samuel 15:22: “And Samuel said, “Has YaHWeH as great delight in burnt offerings and sacrifices, as in obeying the voice of YaHWeH? Behold, to obey is better than sacrifice, and to listen than the fat of rams.”

Psalm 51:16-17: “For you will not delight in sacrifice, or I would give it; you will not be pleased with a burnt offering. The sacrifices of God are a broken spirit; a broken and contrite heart, O God, you will not despise.”

Mark 12:33: “And to love him with all the heart and with all the understanding and with all the strength, and to love one’s neighbor as oneself, is much more than all whole burnt offerings and sacrifices.”

Beside YaHWeH’s Holy festivals you also have to keep His Holy Shabbat as a sign between Him and us for forever:

Exodus 31:12-17: “12 Then YaHWeH said to Moses, 13 “Say to the Israelites, ‘You must observe my Sabbaths. This will be a sign between me and you for the generations to come, so you may know that I am YaHWeH, who makes you holy. 14 “‘Observe the Sabbath, because it is holy to you. Anyone who desecrates it is to be put to death; those who do any work on that day must be cut off from their people. 15 For six days work is to be done, but the seventh day is a day of sabbath rest, holy to YaHWaH. Whoever does any work on the Sabbath day is to be put to death. 16 The Israelites are to observe the Sabbath, celebrating it for the generations to come as a lasting covenant. 17 It will be a sign between me and the Israelites forever, for in six days YaHWeH made the heavens and the earth, and on the seventh day he rested and was refreshed.’”