‘And Reuben heard it and he delivered him out of their hand. And he said, “Let us not take his life.” And Reuben said to them, “Shed no blood. Throw him into this cistern which is in the wilderness but lay no hand on him.” (This was so that he could deliver him from their hand and restore him to his father).'
The repetition ‘and Reuben said' bears all the marks of ancient literature. Reuben may not be as strong and fierce as his brothers but he has more compassion and common sense. He thinks of his father's feelings and he thinks of the stain of fratricide and determines to save Joseph, but the roundabout route is typical of him, although it may have also been wise in the circumstances.
“Let us not take his life.” In other words let us not be directly responsible for his death.
“Shed no blood.” Is he thinking here of Cain who shed his brother's blood? He knows how deeply the world of his day felt about fratricide. Such bloodguilt was a terrible crime which demanded vengeance.
But Reuben's intent was to save Joseph. As the eldest brother he may not have felt the indignity of Joseph's position as deeply as the others and he felt a certain responsibility because of his status.