Earth is a proving planet. Otherwise, God could have created man and placed him in heaven so that he can worship God through eternity straightaway. God did not do that. God does not want human-robots who had been programmed without a will of their own to worship Him. God takes pleasure in true worshippers who will willingly and truly worship Him. If humans were created and placed in heaven, there will be no way to determine those who will exercise the power of their will to serve God and those who will not. Even the angels have wills of their own and can rebel. Lucifer rebelled and became Satan (the Adversary). A third of the angelic hosts rebelled with Satan against God. God wanted man, the crown of His creation, whom He had made in His own image, to be tested for loyalty and obedience. At the end, those who did not give in to the enticements of sin, the world and the devil will be welcome into heaven to be with God through eternity. These people qualify as true worshippers. They have passed the test. They are now fit to be in eternity with their creator.