He can hear everyone's prayers.
So he knows that the dutiful grandson praying for his grandmother to live to a hundred is actually hoping she'll die soon; that the county magistrate praying for favorable weather is really afraid the imperial court will audit his accounts; and that the devout woman kneeling before the statue and bowing until her forehead bleeds is thinking of another man's name.
He has been listening for nineteen years.
Because he is the one inside that statue.