The original calendar of Moses starts in the moon/month of Abib[early spring moon]. Each New Moon, the Yomim[24 hour periods of time beginning at dusk, and lasting till the following dusk] are recalculated, or renewed, or recounted[Our present calendar is Roman/Gregorian and is solar/sun based; very little recalculations are required- every leap year add a day, and by by not making years divisible by 100 to be a leap year.] You will find every observed Sabbath rest in the scripture will occur the 8th, 15th, 22nd, or 29th. Realize when you read "Month" in scripture, it means Moonth/Moon. Passover will always occur the late afternoon of Abib 14; and proceed into the 15th[Full Moon {New Moon is yom 1, special and separate from all the rest of the 29 yomim of the Moon/Month(“In the time of the earliest prophets, the New Moon stood in the same line with another lunar observance, the Sabbath. Ezekiel, who curiously enough frequently dates his prophecies on the New Moon … describes the gate of
the inner court of the -new- temple looking eastward as kept shut for the six working days, but opened on the Sabbath and the New Moon.” Scribner's Dictionary of the Bible -1898 edit., p. 521.
Also: “… each lunar month was divided into four parts, corresponding to the four phases of the moon. The first week of each month began with the new moon, so that, as the lunar month was one or two days more than four periods ofseven days, these additional days -new moon days- were not reckoned at all.” Universal Jewish Encyclopedia, Vol.10, p. 482. Article "Week.").}]
Yom 2,3,4,5,6,7 were/are the six working yomim, while 8 was/is Sabbath. Yom 9, 10, 11, 12, 13, 14 were/are working yomim, while 15 was/is always Sabbath/Full Moon}]. The children of Israel left Egypt the full moon of Abib, Passover night. Messiah instructed his disciples to prepare the "Passover" meal, the night of the betrayal. This was the 14th evening at dusk[precise timing for every Passover since Moses], making His torture and death taking place during "Feast of Unleavened Bread"[Leviticus 23:7]/15th Abib[and Sabbath]. His body was removed from the "tree" before dusk. Late afternoon 15th, all of 16, all of 17 & most of 18 Abib His physical body lay in the tomb. 16 Abib being yom 1[of the week], 17 Abib being yom 2 of the week, 18 Abib being yom 3 of the week, 19 Abib being yom 4 of the week. So, the scripture could very easily have described Mary and the other females taking perfumes to His tomb the 4th yom of the week; BUT it does not.
These 3 Yomim [16,17,18]would normally be[during other months/moons] working yomim[not Sabbaths] but Abib has a special Feast combination within it's time-frame. It has Passover at end of 14th, the 15th[a Sabbath/feast of Unleavened Bread beginning], Feast of First-Fruits[Leviticus 23:11] the 16th[another and unique Sabbath]. How do these Feasts and Sabbaths all fit into the picture? We've got to look at the Calendar Change that took place.
The Priests, Levites, religious leaders in Jerusalem at this time in history were transitioning to a new calendar format[they no longer base their "Sabbath" according to moon cycle: “The New Moon is still, and the Sabbath originally was, dependent upon the lunar cycle.” Universal Jewish Encyclopedia, p. 410. “…the Hebrew Sabbathon … was celebrated at intervals of seven days, corresponding with changes in the moon’s phases...” Encyclopedia Biblica, 1899. p. 4180
The New Testament says that Mary, and the other girls showed up at the tomb "after Sabbath, during the First day of the week" Matthew 28:1;John 20:1. Obviously, this descriptor is utilizing the "New Hellenistic/Roman Calendar". That "First Day" is Sunday[Webster's Dictionary]. So, let's break it down, with the intricate intertwining of feasts, calendar changes, New Moons & Sabbaths.
Messiah followed the original Commands of the Torah, as laid out by Moses, and had Passover meal with His Disciples late afternoon 14 Abib. He was grabbed later by Temple guards just after the 15th had begun[probably 9pm{ish}, the guards carried torches for lighting]. He was tortured, and died late afternoon the 15th. His body had to be removed from the stake[John 19:31] before the Priests, Levites, religious leaders[and probably most of the Jews in Jerusalem] would observe "their Passover"[according to the new calendar]. So Joseph of Arimathea and Nicodemus placed His body in the tomb before the 16th of Abib.
We can interpolate that the 16th of Abib was the time the Priests, Levites, religious leaders celebrated The Feast of Unleavened Bread Sabbath. So, the 16th is the First 24hour period Messiah lay in the Tomb, and it was a Sabbath[Mary and others couldn't trek to the tomb carrying perfumes during an observed Sabbath for fear of retribution]
The following 24 hour period/yom was the 17th of Abib. This would naturally be considered[by the Priests, Levites, religious leaders] the Feast of First Fruits Sabbath[Mary and others couldn't trek to the tomb carrying perfumes during an observed Sabbath for fear of retribution].
The following 24 hour period/yom was the 18th of Abib. At this juncture, we need to consider that Messiah said He would spend 3[full] yom in the tomb[as did Jonah in the whale]. What event could possibly take place to allow for ANOTHER Sabbath? The weekly Sabbath, of course...because Mary came to the tomb "early the first yom of the week". 18 Abib, the priests, Levites and religious leaders observed their weekly Sabbath. So Mary came to the tomb 19 Abib, finding it empty. Of course it was. He'd departed the tomb late afternoon the 18th[which would actually be "Third day"-1Corinthians15:4]. Remember the 15th of each moon/month is Sabbath, 16th is first yom, 17th second yom, 18th is third'.
This whole calendar switching is what throws nearly everybody off. Yeah, according to the Roman Calendar, Mary found the tomb empty the "first day of the week", but scripture Calendar places her find the 3rd day.