“I am the good shepherd. The good shepherd lays down his life for the sheep.
References for John 10:11
The hired hand is not the shepherd and does not own the sheep. So when he sees the wolf coming, he abandons the sheep and runs away. Then the wolf attacks the flock and scatters it.
References for John 10:12
The man runs away because he is a hired hand and cares nothing for the sheep.