God breathes life into Adam in Genesis 2, and Ezekiel 37 associates breath and Spirit with restoration from death.
Genesis 2:7; Ezekiel 37:1-14 are central backgrounds.
Jesus personally breathes and gives the Spirit, fulfilling John the Baptist's earlier testimony that Jesus would baptize with the Holy Spirit.
The action joins resurrection, new creation, divine breath, and Jesus' authority to give the Spirit.
The disciples rejoice when they see the risen Lord.