I'd say it's more likely that it's a coincidence. It often happens by chance that unrelated languages have words that sound similar. For example, in Yucatec Mayan, the word for "hole" is hol, even though English and Mayan are not related at all. There's also an aboriginal language of Australia where the word for "dog" is dog (and it's known that the word was not borrowed from English). So I figure that the similarities here between the Germanic languages and Arabic are also just a coincidence.
That being said, there is at least one prominent linguist, Theo Vennemann, who has proposed that the Germanic languages borrowed a bunch of words from the Semitic languages early in their history. So if he's right, then that could explain this similarity. It is worth noting, though, that most linguists do not take this theory seriously.