2Na_(s) +2H₂O_(l)2NaOH_(aq) +H_2(g)

In this chemical equation, H₂O is the oxidizingagent. I am confused because on the reactant side H₂Ohas an oxidation number of 0. How can we tell that it has reducedif there is no H₂O to compare to on the product side? Iunderstand that a whole compound can be a reducing or oxidizingagent but how can we say that it is the oxidizing agent if we breakit apart on the product side?