We have 200X, the DC comics, the classics, and Revelation & Comics. Which continuity are you referring to mate? 

Posted by: @deltavax

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This is a general question about Grayskull. What made him so special? Why did he have the strength of basically a god? Some people say that he was chosen or connected to either Zoar or the Green Goddess. Can anyone properly explain that? Other than a Reddit post, I'm still kind of lost on that. 

Here you go

https://he-man.fandom.com/wiki/King_D%27Vann_Grayskull

Posted by: @deltavax

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This is a general question about Grayskull. What made him so special? Why did he have the strength of basically a god? Some people say that he was chosen or connected to either Zoar or the Green Goddess. Can anyone properly explain that? Other than a Reddit post, I'm still kind of lost on that. 

The Reddit answers seem to be about the modern DC Comics (2012-2016), that ended with the "Eternity War" storyarc.

They do not say he is "connected to either Zoar or the Green Goddess".
The wiki-link will not help because for some reason they include none of the DC story on that page.

With the modern DC Comics, they referred the all powerful entity by different names. Humans called it "Zoar", Snake Men "Serpos" and Evil Horde called it "Horokoth". But it was the same "god" entity, viewed through different lenses if you will. "Goddess" was one of those names for the same entity, and it has nothing to do with "Green Goddess", who does not exist in the DC Comics. 
Some fans may have confused it, when Teela became the Sorceress of Serpos, and her new design was a nod with the green skin and armor.

In my interview with Rob David, he stated that "What King Grayskull did was build a fortress around the planet's singular access point to Eternia's magic. He did so to protect it from those who would use that magic for evil." and continued "He forged the Sword of Power. He took the power of creation and weaponized it. He did so to save the universe. But it's like when they built the first H-Bomb. Once it was created, it could never be uncreated."

So when Reddit folks refer that King Grayskull connected to Goddess, it's about the Eternity War story. Though I noticed that in the Reddit thread the person originally referred to events in Injustice with Adam against Superman, which are not connected to the earlier storyarc, heh.

It's confusing at times, but in the DC Comics, we have practically three separate canons:

2012-2016 canon ("He-Man and MOTU" that leads into "He-Man the Eternity War")

2017-2019 crossover canon ("Thundercats" and its follow-up "Injustice")

2020 Multiverse story 

Perhaps the OP has moved on to ponder mankind's other mysteries.