To say that man can exist apart from God is to say that a watch can exist without a watchmaker or a story can exist without a storyteller. We owe our being to the God in whose image we are made (Genesis 1:27).
Our existence depends on God, whether we acknowledge His existence or not.
Even those who reject God receive their sustenance from Him He causes his sun to rise on the evil and the good, and sends rain on the righteous and the unrighteous (Matthew 5:45). To think that man can live without God is to suppose a sunflower can continue to live without light or a rose without water.
In Christ Jesus is life, which is the light of men (John 1:4). Christ Jesus came that we may have life and have it to the full (John 10:10). All who place their trust in Him are promised eternity with Him (John 3:15-16). For man to live truly live he must know Christ (John 17:3).
Without God, man has physical life only. God warned Adam and Eve that on the day they rejected Him they would surely die (Genesis 2:17). As we know, they did disobey, but they did not die physically that day; rather, they died spiritually.
The Bible says there is a certain measure of delight to be had in sin (Hebrews 11:25). The problem is that it is temporary life in this world is short (Psalm 90:3-12). Sooner or later, the hedonist, like the prodigal son in the parable, finds that worldly pleasure is unsustainable (Luke 15:13-15).
Without God, man’s destiny is hell. The man without God is spiritually dead when his physical life is over, he faces eternal separation from God.
In Jesus narrative of the rich man and Lazarus (Luke 16:19-31)Man is a unique creation. God has set a sense of eternity in our hearts (Ecclesiastes 3:11), and that sense of timeless destiny can only find its fulfillment in God Himself.