2:259 How Was This Made As A Sign?
When things are explained in detail in previous scriptures, Quran gives a reference to them and defines a boundary and perspective with which to study those details. There are many instances where Quran has done the same.
I agree with that general sentiment to an extent. But we obviously can’t rely on interpretation from previous scriptures since they are even weaker in authenticity than ahadith. And they have been translated many times. But I guess sure the Quran mentions some things like the fish about Musa عليه السلام but someone who doesn’t know the whole story can still take the morals. That’s I guess the beauty of the Quran- unnecessary details are not explored. So if we didn’t have this bible passage we would just say ‘this miracle would’ve obviously been a sign in some way’?