The blog Facts About Religion asks, if we’re dependent on God for our purpose, then who gives God purpose?
But the contention of Christians and other theists is not that “no one can invent his own purpose” or that “every being must receive his purpose from a being above him”. The contention is that God, being the origin of all that exists, is the only one that can give meaning and purpose to our life.
The basis for this contention is that we are contingent beings. This means that we can either exist or not exist, and that we are dependent for our existence on things outside ourselves. Not even an atheist can deny this.
Since we don’t even receive our existence from ourselves, it stands to reason that we can’t get the reason for our existence from ourselves.
God’s case is entirely different from our own. Since he is the origin of all things, he must exist, and does not depend for his existence on anything outside himself. It stands to reason therefore that he is not dependent for the reason for his existence on anything outside himself.