" —That Thou Art Mindful of Him!" by Isaac Asimov

First appeared in F&SF, reprinted twice, and nominated for a Hugo and Locus awards.

Georges Nine and Ten, two robots, are given the task of figuring out how robots and humans can coexist. This complicated by the fact that some humans are untrustworthy of giving commands, and the robots must obey the second law except if it violates the first:

1. A robot may not injure a human being or, through inaction, allow a human being to come to harm. 
2. A robot must obey the orders given to it by human beings, except where such orders would conflict with the First Law. 
3. A robot must protect its own existence as long as such protection does not conflict with the First or Second Law.

They have to consider that:

"(A) an educated, principled and rational person should be obeyed in preference to an ignorant, immoral and irrational person, and (B) that superficial characteristics such as skin tone, sexuality, or physical disabilities are not relevant when considering fitness for command."

 Since the robots have metal skin and are more rational, they should be considered human and their commands obeyed. They create the Three Laws of Humanics.

There seem to be infinite variations on these three simple laws. Supremely clever if a little long.