Van Slyke

Hence blessing or consecrating a thing in general or
water in particular entailed breaking Satan’s influence
over it, so that it could no longer serve as an instrument
of his hate.54 Then, by the power of Christ entrusted
to the Church, the thing blessed could be used as an
efficacious instrument for good – assuming the proper
disposition of the person who benefits from the use of
the item.

- Daniel G. Van Slyke, "The Order for Blessing Water: Past and Present," Antiphon 8, no.2 (2003), 18.