The offering of the first fruits of the barley harvest, called the Wave Offering, comes from the commandment found in Leviticus 23:9-11, which states,
And the Lord spake unto Moses, saying, Speak unto the children of Israel, and say unto them, When ye be come into the land which I give unto you, and shall reap the harvest thereof, then ye shall bring a sheaf of the firstfruits of your harvest unto the priest: And he shall wave the sheaf before the Lord, to be accepted for you: on the morrow after the sabbath the priest shall wave it
The phrase "on the morrow after the sabbath" was the source of intense disagreement between the Pharisees and the Sadducees. The Pharisees understood the sabbath to mean the feast day, the 15th of Nisan, being one of the seven annual sabbaths listed in Leviticus 23. The Sadducees took it to mean the regular weekly Sabbath. This is just one more witness to the fact that during the week of Passover, there were considered to be two Sabbaths.
Since the Sadducees, who were comprised predominantly of the priests, were in control of the temple services and rituals, theirs was the prevailing practice, at least until the destruction of the temple in AD 70. At that point, the Pharisees took control of Judaism, which it then developed into Rabbinic or Talmudic Judaism.
It is a fairly well established fact, that since the Sadducean method of calculating the wave offering was the one practiced, we have a very good idea of how they accomplished it.
At the end of the weekly Sabbath, as the first day of the week was beginning ("the morrow after the sabbath"), they would with great fanfare go to the field that had been set aside for such purpose, and reap the previously bundled stalks of barley. They would cut the standing stalks of barley free from the earth. This is a picture of the resurrection of Christ from the dead. When Jesus was resurrected, He was set free from this earthly realm.
The barley stalks were then prepared for the priest to make the wave offering the next morning. The wave offering, which consisted of an omer of barley, was waved, or "lifted up" before the Lord on the morning of the first day of the week. This gives us an understanding of the saying of Jesus to Mary, when she saw Him at the tomb. John 20:17 records this,
Jesus saith unto her, Touch me not; for I am not yet ascended to my Father:but go to my brethren, and say unto them, I ascend unto my Father, and your Father; and to my God, and your God.
With regard to Jesus fulfilling the Firstfruits Offering, we see that as the bundled stalks of barley were being harvested and cut free from their earthly bonds in preparation to their being presented to God, so Christ, who was bundled in His grave clothes, was being raised from the dead, being set free from His earthly bond to incorruption. Both of these events were occuring at the same time.
The fact that the resurrection of Jesus took place at the same time as the harvesting of the firstfruits of the barley harvest, would seem to lend support to the idea that the Sadducees had the timing and interpretation of the "morrow after the sabbath" correct. For God does not bend his feasts and their fulfillment to the whim of man's interpretation, such as the pharisaic tradition.