Why did Jesus breathe on the disciples?

In John 20, Jesus breathed the Holy Spirit upon the disciples, but later in Acts we find Pentecost. In which moment did the disciples receive the Holy Spirit?

In John 20, we read:

John 20:22 And when He had said this, He breathed on them and said to them, “Receive the Holy Spirit.

Jesus performed this work upon 10 of the eleven disciples (Thomas was not present). Was this the moment that these ten men received the indwelling of the Spirit, as Christ promised to them in the Upper Room discourse?

Apparently not, because in Acts we read:

Acts 1:2 until the day when He was taken up to heaven, after He had by the Holy Spirit given orders to the apostles whom He had chosen.
Acts 1:3 To these He also presented Himself alive after His suffering, by many convincing proofs, appearing to them over a period of forty days and speaking of the things concerning the kingdom of God.
Acts 1:4 Gathering them together, He commanded them not to leave Jerusalem, but to wait for what the Father had promised, “Which,” He said, “you heard of from Me;
Acts 1:5 for John baptized with water, but you will be baptized with the Holy Spirit not many days from now.”
Acts 1:6 So when they had come together, they were asking Him, saying, “Lord, is it at this time You are restoring the kingdom to Israel?”
Acts 1:7 He said to them, “It is not for you to know times or epochs which the Father has fixed by His own authority;
Acts 1:8 but you will receive power when the Holy Spirit has come upon you; and you shall be My witnesses both in Jerusalem, and in all Judea and Samaria, and even to the remotest part of the earth.”
Acts 1:9 And after He had said these things, He was lifted up while they were looking on, and a cloud received Him out of their sight.

Notice this scene involves the apostles, as Luke says in v.2. The apostles were the same men as those present in John 20, so whatever Jesus did in John 20, we know He did NOT give the apostles a permanent indwelling of the Spirit at this moment, otherwise the Spirit would not have come again to them in Acts 2. Notice in Acts 1:8 Jesus speaks in the future tense about the coming of the Spirit to these men.

Furthermore, the Spirit could not come upon these men prior to Pentecost because the Jewish feast of Pentecost is fulfilled by the Spirit’s arrival to the Church. The Law was given to Israel at Mt. Sinai 50 days after the first Passover and Israel's exodus from Egypt. Likewise, the law of God is written on the hearts of believers 50 days after the sacrifice of Christ, our Passover. That feast could not be fulfilled prematurely, just as Jesus could not have died on the cross a day sooner than Passover.

Therefore, how do we interpret the events of John 20? In all probability, Jesus was giving His disciples a symbolic and memorable introduction to the Spirit, Who was to come upon them later. This moment was a demonstration of what Jesus would do at Pentecost after He returned to the Father.

Breath is often a picture of the Spirit (in fact, the Hebrew word for Spirit is also the word for breath), so Jesus “breathed” on the men while He was standing with them in His physical presence to indicate what He was preparing to do later by the Spirit. Therefore, Jesus was not imparting the Spirit to them in John 20 in any real sense. He was promising to do so later at Pentecost.

Remember, Thomas was not present at the moment, so had the Spirit been given as some might argue, how then would we explain Thomas’ absence? Did he not receive the Spirit? This dilemma is solved by concluding the Spirit was not involved in this moment, expect as symbolized by Jesus’ breath. It also explains why this event had no permanent impact on the disciples comparable to that of Pentecost.

Evidently there was only one coming of the Spirit on these disciples, and that happened on Pentecost.