Twice in Genesis we are told that Joseph gave Benjamin much more than he did his brothers. First, he gives him five more portions of food than the rest and as they were leaving to fetch Israel, he gave Benjamin silver and five changes of clothing as opposed to the one change of clothing he gave his brothers.
Many ask why he did this. The text itself does not clearly state so we can only speculate, but there are a few plausible thoughts on this and one, all, or none may be the case.
1. Benjamin was Joseph’s full brother, with them sharing Rachel as a mother. Further, he and Benjamin were Rachel’s only children.
2. Rachel died giving birth to Benjamin, no doubt placing an even more special feeling of responsibility and care in Joseph’s heart for him.
3. Joseph was a younger brother when he was taken away, but he was still older than Benjamin. While he had years to know his brothers, his relationship with Benjamin was comparatively short-lived. It was this relationship that he missed out the most on, having very little time with him before being taken to Egypt. Their bond would have no doubt been a very special one and this could easily be Joseph showering his younger brother with affection and love for all that the two of them had missed out on. I think of this as I would a grandparent who had lived far away and the first time they see their grandchild they show up with tons of gifts.
4. This could have also been another way of honoring his late mother, by showing greater honor to her youngest child.
As I said, the text does not say but any of the above reasons are plausible possibilities and it could very well be a combination of all of them.