He runs because he is a hired hand, and the sheep mean nothing to him.
In context
11I am the good shepherd. The good shepherd lays down his life for the sheep. 12The hired hand, who is no shepherd and does not own the sheep, sees the wolf coming, abandons the sheep and runs — and the wolf seizes them and scatters them. 13He runs because he is a hired hand, and the sheep mean nothing to him. 14I am the good shepherd. I know my own, and my own know me, 15just as the Father knows me and I know the Father; and I lay down my life for the sheep.
