John 20:16-17 NLT‬
[16] “Mary!” Jesus said. She turned to him and cried out, “Rabboni!” (which is Hebrew for “Teacher”). [17] “Don’t cling to me,” Jesus said, “for I haven’t yet ascended to the Father. But go find my brothers and tell them, ‘I am ascending to my Father and your Father, to my God and your God.’”

The Greek word “haptomai” can be translated “touch” or “attach oneself to”. After the resurrection, outside the tomb, as Mary instinctively desired to touch or cling to Jesus in her joy, Jesus cautioned her not to do it. Why?

Under the Old Covenant, on the day of atonement, Yom Kippur, the high priest went into the Most Holy Place in the tabernacle with the blood of the annual sacrificial offering for the sin of the nation. He sprinkled the blood on the Mercy Seat to atone for Israel’s sin, then he left the Most Holy Place, alive, to sit down as an indication that God had accepted the sacrifice. No one was permitted to touch him until he had sat down to finish the work of atonement for another year.

However, the high priest could never sit down permanently as a fallen human. The fact that he stood up again indicated that his work was not permanent. He was acting out a ritual that only Jesus could fulfil.

‭Hebrews 9:25-26 NLT‬
[25] “And he (Jesus) did not enter heaven to offer himself again and again, like the high priest here on earth who enters the Most Holy Place year after year with the blood of an animal. [26] If that had been necessary, Christ would have had to die again and again, ever since the world began. But now, once for all time, he has appeared at the end of the age to remove sin by his own death as a sacrifice.”

‭Hebrews 10:11-12 NLT‬
[11] “Under the old covenant, the priest stands and ministers before the altar day after day, offering the same sacrifices again and again, which can never take away sins. [12] But our High Priest offered himself to God as a single sacrifice for sins, good for all time. Then he sat down in the place of honor at God’s right hand.”

Since Jesus’ realm is in the eternal now, it is difficult for us to understand whatever sequence of events took place throughout the cross and resurrection events. What we do understand from Scripture is that He offered Himself as one sacrifice, once for all, in the heavenly tabernacle, sprinkled His own blood on the Mercy Seat for the forgiveness of sin, then sat down at the right hand of the Father to reign as Lord.

‭Hebrews 8:1-5 NLT‬
[1] “Here is the main point: We have a High Priest who sat down in the place of honor beside the throne of the majestic God in heaven. [2] There he ministers in the heavenly Tabernacle, the true place of worship that was built by the Lord and not by human hands. [3] And since every high priest is required to offer gifts and sacrifices, our High Priest must make an offering, too. [4] If he were here on earth, he would not even be a priest, since there already are priests who offer the gifts required by the law. [5] They serve in a system of worship that is only a copy, a shadow of the real one in heaven. For when Moses was getting ready to build the Tabernacle, God gave him this warning: “Be sure that you make everything according to the pattern I have shown you here on the mountain.”

‭Hebrews 10:1 NLT‬
[1] “The old system under the law of Moses was only a shadow, a dim preview of the good things to come, not the good things themselves. The sacrifices under that system were repeated again and again, year after year, but they were never able to provide perfect cleansing for those who came to worship…
[11] Under the old covenant, the priest stands and ministers before the altar day after day, offering the same sacrifices again and again, which can never take away sins. [12] But our High Priest offered himself to God as a single sacrifice for sins, good for all time. Then he sat down in the place of honor at God’s right hand. [13] There he waits until his enemies are humbled and made a footstool under his feet.”

So, to Mary He cautioned, “Don’t touch me. I have not yet sat down to complete the purpose of my sacrifice.”

However, to Thomas He had a different invitation.

‭John 20:24-27 NLT‬
[24] “One of the twelve disciples, Thomas (nicknamed the Twin), was not with the others when Jesus came. [25] They told him, “We have seen the Lord!” But he replied, “I won’t believe it unless I see the nail wounds in his hands, put my fingers into them, and place my hand into the wound in his side.” [26] Eight days later the disciples were together again, and this time Thomas was with them. The doors were locked; but suddenly, as before, Jesus was standing among them. “Peace be with you,” he said. [27] Then he said to Thomas, “Put your finger here, and look at my hands. Put your hand into the wound in my side. Don’t be faithless any longer. Believe!”

It seems, then, that this incident with Thomas reveals that His atoning sacrifice was accepted and His work complete, allowing all who believe in Him, in the spirit to “touch” Him, to have personal and intimate fellowship with Him because there is no longer any obstacle or barrier between us and Him.