Zina.

[waraabe]

Time to modernise. Say no stoning

 

[bluebird]

Between these two posts of 1) Hadd being established through confesssion and the stringency of the 4 witnesses being an anti-slander measure based on hiding sin and honoring ppl 2) The prophet suggesting it's better to conceal one's sins.

What function does the punishment serve?

what the man above said, and it's pretty much reserved for the most shameless of people who would do it in front of a crowd of people if you think about it. Unless they confessed on their own accord