"It isn't so wise to snoop, or you'll finish up in the soup" is just of the lines in the lyrics to "Curiosity Killed The Cat" as sung by a mother penguin here to her four little ones, who are snooping around a log cabin, peeking in the windows and such.
That's the moral to this cartoon, another of the Technicolor cartoons of the period by Dave Fleischer, who put a number of these "moralistic" messages in addition to a bunch of loony cartoons. No, these obviously aren't nearly as much fun as Fleischer's wacky stuff but I suppose they did serve a purpose to little kids back in the mid-to-late '30s.
The penguins ignore mom's advice, find a way into the cabin, have fun for awhile but then pay the price. The gags are kind of lame but small kids would probably laugh at them. One good thing: it's fast-paced, with a lot of action. It isn't bad, but this is not something an adult would watch more than once.