Surah 12. Yusuf, Ayah 14

Jacob's objections as stated could be easily rebutted, and the brethren did so. They would be eleven in the party, and the ten strong and grown-up men would have to perish before the wolf could touch the young lad Joseph! So they prevailed, as verbal arguments are apt to prevail, when events are weaving their web on quite another Plan, which has nothing to do with verbal arguments. Presumably Benjamin was too young to go with them.