As'salamu Alaikum sister Sharon and Everyone,
89:9 وثمود الذين جابوا الصخر بالواد
[089:009] And with the Thamud (people), who cut out (huge) rocks الصخر in the valley?-
The AL (the) article in Arabic here is not referring to certain rocks. It's referring to rocks in general. It's Arabic grammar. The "the" and "a" and "an" articles can all be used in the "AL" in Arabic. Even in English, if you use the "THE" article to unknown subjects, then it can refer to general subjects and not specific ones. Take this example:
"Sharon saw the kids playing in the playground, where there was a church that had pedophile priests in it."
Here kids doesn't refer to kids that Sharon necessarily knew. It's referring to random kids in general. In fact, the "THE" article in "the kids" is general, while the "a" article in "a church" is specific. And the "the" in "the playground" is specific.
You could also add THE to "pedophile priests in it" and still be referring to general subjects, because you may not necessarily knew them, but you've heard about them from other people and on the news.
The Arab Christians that are feeding you the load of nonsense are leading you astray, my dear sister in Islam. They are known to be weak in the classical Quranic Arabic.
And "the load of nonsense" is also referring to general nonsense that they will try to deceive you with.
Take care,
Osama Abdallah