Israel was not exempt from the first three plagues upon
Egypt, because they needed to be cleansed from Egyptian idolatry (Exodus 8:22-23 cf.Deuteronomy 32:15-17)
Blood is also that which sustains the life of the flesh
and is, therefore, required as the atonement for a life that is alienated from God (Leviticus 17:11)
God uses the expression, "voice", to amplify
the meaning of physical things by means of personification as in the case of Abel's spilt blood (Genesis 4:10)