Let's start with the basic word physao (fu SAH oh), which meant in ancient Greek to "puff, snort, or blow." It referred to letting out a blast of air, as from a bellows in a blacksmith's shop. It was the word to be used when someone blew up a bladder or a balloon.
Now let's add the prefix em- which means "in, on, or into." Our compound word emphysao will mean to take a big breath and blow into or toward something.
When we have this idea clearly in mind, we are ready to look at the only time emphysao is ever used in the New Testament. In John 20:22 Jesus appeared to his disciples on the evening of his resurrection. As a part of sending them out with the gospel, "He breathed on them and said, 'Receive the Holy Spirit.'" Jesus was clearly preparing these men for their special reception of the Spirit and power which would come at Pentecost (Acts 1:4-8; 2:1-4). But why did Jesus puff at them? Is there more here than meets the eye?
The first century readers of John's gospel would probably have caught the fact that his use of the word emphysao was a reminder of at least three key passages in the Old Testament. It was the same word used in Genesis 2:7 when the LORD God formed Adam from the dust of the ground and "breathed into his nostrils the breath of life." Likewise, the word was later found in scripture when Elijah stretched himself over the lifeless son of the widow and resuscitated him (1 Kings 17:21). Finally, a similar image was found in Ezekiel 37:9, where the prophet told God's Spirit to breathe upon the valley of dead bones and bring them back to life.
So what can we conclude? Jesus was preparing the disciples for a mighty infusion of life -- spiritual life. Inflated by the breath of God himself, these men received new life which they then imparted to all the world. A new creation had begun!