In his book, Making Sense of God, Timothy Keller has two excellent chapters on identity. He makes the point that when our identity is received from God we are relieved from finding it in others, in our work, or in our own shifting views. He says:
Your work is still part of your identity, as are your family, your nationality, and so on. But they are all relieved of the terrible burden of being the ultimate source of your self and value. They no longer can distort your life as they do when they are forced into that role. They are, as it were, demoted to being just good things. Work is no longer something you use desperately to feel good about yourself. It becomes just another good gift from God that you can use to serve others.