Every person must find some way to "justify their existence", states Kierkegaard. to stave off the universal fear that they're 'a bum.' In more traditional cultures, the sense of worth and identify comes from fulfilling duties to family and giving service to society. In our contemporary individualistic culture, we tend to look to our achievements, our social status, our talents, or our love relationships. Some get their sense of 'self' from gaining and wielding power, others from human approval, others from self-discipline and control, But everyone is building their identify on something.
Identify apart from God is inherently unstable. For example, if I build my identity on being a good parent, I have no true 'self'' - I am just a parent, nothing more. If something gores wrong with my children or my parenting, there is no 'me' left.
If anything threatens your identity you will not just be anxious but paralyzed with fear. If you lose your identity through the failings of someone else you will not just be resentful, but locked into bitterness. If you lose it through your own failings, you will hate or despise yourself as failure as long as you live.
Only if your identify is built on God and his love, says Kierkegaard, can you have a self that can venture anything, face anything.
From the book "The Reason for God" by Timothy Keller