[ ... ] a late Islamic fabrication because of the confusion in Islamic times which made it such a capacious term as to include the inhabitants of the south as well as the north of the Arabian Peninsula . But shorn of this extravagance , the concept is much more modest in its denotation , and in the sober sources it apply only to certain groups among the Arabs of pre @-@ Islamic times . Some important statements to this effect was made by Muhammed when he identified some Arabs as Ishmaelites and others as not .