r/u_Classic_Mastodon_430

Arabic and Hebrew are equally old. They are both continua of Proto-Semitic, the common ancestor of all Semitic languages. The only difference is that Hebrew is attested earlier than Arabic in writing. A language exists independently of whether or not it was written down, so Arabic existed one way or another.

I see claims such as "Arabic is Modern compared to Biblical Hebrew"

It's not.

Look up how Proto-Semitic conjugates the verb kataba, then in Arabic. Across ~ 6,000 years, Classical Arabic has almost the exact same conjugations as its Proto-Semitic ancestor. Does that made Arabic any less than 2,000 to 3,000 years old, better yet, 4,000?