Totally incorrect. First and seventh ULB are called "holy convocations." They are never called a Sabbath anywhere in either testament. Neither day has a day of preparation since preparing and cooking food is specifically permitted on both days.
Exodus 12:15-16
15 Seven days shall ye eat unleavened bread; even the first day ye shall put away leaven out of your houses: for whosoever eateth leavened bread from the first day until the seventh day, that soul shall be cut off from Israel.
16 And in the first day there shall be an holy convocation, and in the seventh day there shall be an holy convocation to you; no manner of work shall be done in them, save that which every man must eat, that only may be done of you.
There was only one Sabbath in passion week, the weekly Sabbath and there was only one "Parasceue," which means "preparation," then and now in Greek, the Friday before the weekly Sabbath.
Is the Passover lamb ever called a sacrifice in the O.T.?
Well that's true it didn't actually say sabbath day, but we still call it a high holy sabbath day because the other feast days are call sabbaths.
Let's go to Leviticus 23: 1 And the Lord spake unto Moses, saying,2 Speak unto the children of Israel, and say unto them,
Concerning the feasts of the Lord, which ye shall proclaim to be holy convocations, even these are my feasts.
All of these are not feast, but you notice the Lord says
even these are my feasts.
3
Six days shall work be done: but the seventh day is the sabbath of rest, an holy convocation; ye shall do no work therein: it is the sabbath of the Lord in all your dwellings. 4
These are the feasts of the Lord, even holy convocations, which ye shall proclaim in their seasons.
All so notice that these are the feast to Lord and not the Jews.
5 In the fourteenth day of the first month at even is the
Lord's passover.
Now the passover don't say have a holy convocation, but we all go to church and take the bread and wine.
6 And on the fifteenth day of the same month is the
feast of unleavened bread unto the Lord: seven days ye must eat unleavened bread.
7 In the first day ye shall have an
holy convocation: ye shall do no servile work therein. 8 But ye shall offer an offering made by fire unto the Lord seven days: in the seventh day is an holy convocation: ye shall do no servile work therein.
23 And the Lord spake unto Moses, saying, 24 Speak unto the children of Israel, saying, In the seventh month, in the first day of the month,
shall ye have a sabbath,
a memorial of blowing of trumpets, an holy convocation. 25 Ye shall do no servile work therein: but ye shall offer an offering made by fire unto the Lord.
26 And the Lord spake unto Moses, saying, 27 Also on the tenth day of this seventh month there shall be
a day of atonement: it shall be an
holy convocation unto you; and
ye shall afflict your souls, and offer an offering made by fire unto the Lord. 28 And ye shall do no work in that same day: for it is a day of atonement, to make an atonement for you before the Lord your God.
29 For whatsoever soul it be that shall not be afflicted in that same day, he shall be cut off from among his people. 30 And whatsoever soul it be that doeth any work in that same day, the same soul will I destroy from among his people. 31 Ye shall do no manner of work: it shall be a statute for ever throughout your generations in all your dwellings. 32
It shall be unto you a sabbath of rest, and ye shall afflict your souls: in the ninth day of the month at even, from even unto even, shall ye celebrate your sabbath.
Notice on this day you afflict your souls, meaning fast.
33 And the Lord spake unto Moses, saying, 34 Speak unto the children of Israel, saying, The fifteenth day of this seventh month shall be the
feast of tabernacles for seven days unto the Lord. 35 On the first day shall be an
holy convocation: ye shall do no servile work therein. 36 Seven days ye shall offer an offering made by fire unto the Lord: on the
eighth day shall be an holy convocation unto you; and ye shall offer an offering made by fire unto the Lord: it is a solemn assembly; and ye shall do no servile work therein.
37
These are the feasts of the Lord, which ye shall proclaim to be holy convocations, to offer an offering made by fire unto the Lord, a burnt offering, and a meat offering, a sacrifice, and drink offerings, every thing upon his day:
38
Beside the sabbaths of the Lord, and beside your gifts, and beside all your vows, and beside all your freewill offerings, which ye give unto the Lord.
39 Also in the fifteenth day of the seventh month, when ye have gathered in the fruit of the land, ye shall keep a feast unto the Lord seven days:
on the first day shall be a sabbath, and on the
eighth day shall be a sabbath.
Notice this high sabbath day have a first day an a eight day. Unleavened bread have first day and seven day.
Is the Passover lamb ever called a sacrifice in the O.T.?
In the OT the Atonements was a high sabbath that represented the sacrifice lamb, which was Jesus, for the day of passover, which his death.