Guards against Evil

I noticed these statues for the first time the other day, fairly high up on the side of a building on the Marnixstraat in Amsterdam. Rather risqué if you ask me (what's with the naked man and boy?) and particularly curious since the building is the head office of the Amsterdam police. The text above/behind says:

't Gezag dat rust behoudt in stad en staat, waakt rusteloos tegen d'onrust van het kwaad

which translates roughly as:

The authority that maintains calm in city and State, guards relentlessly against the restlessness of evil.