Why did Mary Magdalene and the other women disciples wait until dawn of Sunday before arriving at the tomb?
It is because, for the disciples, the Sabbath day ended not at sunset on Saturday evening, but at dawn on Sunday morning.
It is for the same reason that the women bought spices the day after the Sabbath (Mark 16:1) and prepared them the same day which was simultaneously the day before the Sabbath (Luke 23:56). It is for the same reason that both Mark and Luke could say that the Passover lamb was killed on the first day of unleavened bread (Mark 14:12; Luke 22:7), whereas it is generally agreed the lambs were killed in the afternoon of the 14th Nisan and eaten after sunset which was the 15th, i.e. not the same day but a new day. And it is for precisely the same reason the Last Supper both was a Passover meal (Matthew 26:17; Mark 14:12; Luke 22:8, 15) and yet it wasn’t eaten at the time the priests ate the Passover meal (John 18:28) or on the day approved for all by the Temple authorities.
And the women also, which came with him from Galilee, followed after, and beheld the sepulchre, and how his body was laid. And they returned, and prepared spices and ointments; and rested the Sabbath day according to the commandment.
24 Now upon the first day of the week, very early in the morning, they came unto the sepulchre, bringing the spices which they had prepared, and certain others with them. (Luke 23:55-24:1, KJV)
In the end of the Sabbath, as it began to dawn toward the first day of the week, came Mary Magdalene and the other Mary to see the sepulchre. (Matthew 28:1, KJV)
The official Jewish Calendar in the time of Christ
The official calendar of the Jews in the time of Christ was derived from the Babylonians. It was adopted by the Jews while they were in captivity. The Jewish month names are mostly taken from the Babylonian names. E.g. the Jewish name of month 1 was “Nisan” the Babylonian name was “Nisanu”; month 2, “Iyyar” from “Aiaru”; month 3, “Sivan” from “Simanu”; month 5, “Ab” from “Abu”; 6, “Elul” from “Ululu”; 7, “Tishri” from “Tashritu”; “Kislev”, “Kislimu”; “Tebeth”, “Tebetu”; “Shebat”, “Shabatu”; “Adar”, “Adaru”. In this calendar each day begins, and the date changes, at sunset.
Which Jews went into captivity?
And he carried away all Jerusalem, and all the princes, and all the mighty men of valour, even ten thousand captives, and all the craftsmen and smiths: none remained, save the poorest sort of the people of the land. And he carried away Jehoiachin to Babylon, and the king's mother, and the king's wives, and his officers, and the mighty of the land, those carried he into captivity from Jerusalem to Babylon. (2 Kings 24:14-15).
The elite, the educated were taken into captivity, the poor were left behind. When the elite returned they brought back the Babylonian Calendar with them.
But what calendar did the Israelites have before this? Before this they had the calendar given to them by God through Moses. And this calendar was exactly the same as the Egyptian Calendar used for religious purposes, except that the Israelites were to call the month of the Spring equinox the first month of the year.
And the Lord spake unto Moses and Aaron in the land of Egypt saying, This month shall be unto you the beginning of months: it shall be the first month of the year to you (Exodus 12:1-2, KJV).
Because the Egyptian year consisted of lunar months of 29 or 30 days each, then twelve lunar months totalled about 354 days and every few years an extra lunar month was added to keep the months in step with the solar year, and to ensure the Passover feast fell within the first month following the Spring equinox.
For the Israelites this was achieved by making sure the harvest was fully gathered in before the 15th of the 7th month. If the harvest was not finished then an extra 7th month was added, as implied by this text:-
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. (Leviticus 23:39, KJV)
The difference between the Egyptian Calendar and the Babylonian Calendar
Each month the moon entirely disappears and this is the New Moon.
In the Babylonian Calendar the beginning of the month is determined by the first appearance of the new crescent moon after the New Moon. Because the new crescent moon first appears in the evening sky the first day begins after dark, and each subsequent day of the month begins in the evening at sunset.
In the Egyptian Calendar the beginning of the month is determined by the disappearance of the old crescent moon; i.e. the first day there is no moon at all because the old crescent moon has finally gone, and on the day the moon has disappeared this is treated as the first day of the month. And because the old crescent moon is last seen in the early morning the first day starts in the morning; each subsequent day of the month therefore also begins at dawn.
This is the calendar that formed the basis of the calendar God gave to Moses to give to the Israelites when they left Egypt (Exodus 12:1-2). From the time they left Egypt until the time of the Babylonian captivity the Israelites used this calendar. Let me call it the Mosaic Calendar.
There are two essential differences between the Mosaic Calendar and the Babylonian Calendar.
First, in the Mosaic Calendar each day begins, and the date changes, at dawn; but in the Babylonian Calendar each day begins, and the date changes, at sunset.
Second, because the disappearance of the old crescent moon happens about two days before the appearance of the new crescent moon, the dates of the month in the Mosaic Calendar are usually two days ahead of the Babylonian Calendar. For instance, when it is 14th Nisan in the Mosaic Calendar it is 12th Nisan in the Babylonian Calendar.
The calendar for the poor and illiterate verses the calendar for the elite
It was the elite that were taken into Babylonian captivity and brought back the Babylonian Calendar, the poor, illiterate, etc were left in the land of Israel and continued with the Mosaic Calendar (2 Kings 24:14-15). When the elite wanted to impose the Babylonian Calendar not everyone accepted it; they continued with the Mosiac Calendar. So from the time of the return from captivity until the New Testament era there were two calendars in use: the Temple elite used the Babylonian and the uneducated, the poorer folk used the Mosaic.
The Galileans used the Mosaic Calendar.
Each group – poor and elite – celebrated Passover according to their own calendar. So the disciples killed the Passover Lamb on the afternoon of Wednesday 14th Nisan (Mosaic Calendar) and ate the Passover meal after sunset on Wednesday which was still the 14th Nisan.
In the early hours of Thursday morning, during the night, Jesus was arrested. The disciples observed the first day of unleavened bread on Thursday 15th Nisan (Mosaic Calendar) as a special Sabbath, from dawn to dawn of Friday morning (Leviticus 23:6-7, Exodus 12:16).
On Friday our Lord died in the afternoon while the lambs were being killed at the Temple on Friday 14th Nisan (Babylonian based Calendar). On this day also after Thursday the 15th Nisan (Mosaic) Sabbath (Mark 16:1, Exodus 12:16, Lev 23:6-7), the women bought and prepared spices to anoint the body of Jesus which was before the Saturday Sabbath (both calendars) (Luke 23:56). On Friday 14th Nisan (Babylonian) the body was taken down and buried by Joseph of Arimathaea in a nearby tomb before Friday sunset which was the start of the Saturday Sabbath of the Temple authorities. This Sabbath was a high day according to the Temple-approved Babylonian-based calender because it was a Saturday Sabbath and a Sabbath because it was the 15th Nisan, the first day of unleavened bread (John 19:31). The disciples of our Lord complied with the demands of the authorities in keeping the Sabbath from the time of the Friday sunset.
But they rested until Sunday dawn because that was the time the Saturday Sabbath ended according to their Mosaic Calendar.
This answer is based on the work of mainly Professor Colin Humphreys together with checkers and helpers such as Peter Williams and others at Trinity House, Cambridge.
For further study see “The Mystery of the Last Supper” by Colin Humphries, 2011.