Because, as the apostle Paul explains:

“Do you not know that all of us who were baptized into Christ Jesus were baptized into his death? Therefore we were buried with him through our baptism into his death, in order that, just as Christ was raised up from the dead through the glory of the Father, we also should likewise walk in a newness of life.

These, then, have figuratively “died.” After they have the benefits of Christ’s sacrificial death for their sins applied to them, they are declared or ‘counted’ righteous. (Rom. 5:1, 18; 8:30) Their fleshly bodies, with their old personalities, are counted as impaled with Christ. They are then spiritually begotten by God, giving them hope of life in the spirit. (John 3:5-8) Their hope is no longer set on earthly things.