Everyone struggles to justify their existence. Although, I think that often our generation just tries to escape. It's fairly easy to live in a world of entertainment--a false reality. But even so, we cannot do this for long. Inevitably, there has to be some meaning in life. We need to have some sense of worth and purpose.
Everyone has their identity in something. The thing that you absolutely cannot live without--a successful career, family, lover, intelligence, money, or friends--whatever that thing is, that is your identity. It is what your life is centered on. It is what makes you feel fulfilled.
Some of these things are good in and of themselves, but as Tim Keller says in his book, Reason for God:
If we take our meaning in life from our family, our work, as cause, or some achievement other than God, they enslave us...The good things that enslave us are good things that deserve to be loved. But when our heart loves become inordinate, then we fall into patterns of life that are not unlike substance addiction. (p. 165)
The problem becomes apparent when one of these things fails you. Who are you then?
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 a failure as long as you live. (p. 165)
Biblically speaking, putting our identity in anything other than God is sin. To value something more than Christ is in the truest sense idolatry. I think we often don't realize how much we value something until we are threatened with losing it. If there is something other than Christ that we cannot live without, we are on very unstable ground.
We may think we are independent--that we don't need anyone or anything. But what if our independence is taken away? Who are we then? We always live for something. Whatever that something is controls us. It becomes our master. I know that some people feel that Christ is a hard master and that Christianity is a straightjacket. I couldn't disagree more. As Keller says,
If Jesus is your center and Lord and you fail him, he will forgive you. Your career can't die for your sins. You might say, "If I were a Christian I'd be going around pursued by guilt all the time!" But we all are being pursued by guilt because we must have an identity and there must be some standard to live up to by which we get that identity. Whatever you base your life on--you have to live up to that. Jesus is the one Lord you can live for who died for you--who breathed his last breath for you. Does that sound oppressive?... Jesus is the only Lord who, if you receive him, will fulfill you completely, and, if you fail him, will forgive you eternally. (p.172-173)
Having my identity in Christ brings me so much joy. Jesus has shown me such kindness, compassion and patience. He has gently wooed me and healed me. His great love has melted my heart of stone and replaced it with a heart of flesh. I find it a beautiful thing to rest in Him.
Note: I have referenced Tim Keller in this note because I have recently read him and found him to be remarkably insightful into the inner workings of my heart. However, I really should footnote my beloved husband who has taught me everything I know about having my identity in Christ.