We're talking about the one human being in the world who had the power to die and come back to life for more than a month in the first century of our present era. He is also the man that has been regarded as the wisest and most ethical human being by both religious and non-religious philosophers. He behaved and spoke as one would expect the son of the creator to behave, and he said that you and I were made inside him before the world was created.
Why would our maker make us inside his only son ? This man's resurrection, you remember, is so reliably reported in history and fully documented in thousands of manuscripts that our very history is divided into B.C. and A.D.. He explained his final departure from the earth by saying "I go to prepare a place for you that where I am there you may be also". It's plain from his other statements that the creator is a loving person who made us because he wanted other children like his only son. He obviously made us in his son so that we would share his life and nature and be as dear to him personally. But Jesus made it clear that his father did not want little toy automatons but free-will people who could actually be friends that he could love. This meant we could choose non-existence if we wanted, so he would have to sustain us and bear the consequences while we chose. He did this by making us inside his own son. So our present world is the temporary effect of our current decision to live in independent nothingness !
It also explains why so many of us have within us good and kindly impulses along with selfish and cruel attitudes. The goodness comes from this life of Christ within us while the hostile attitudes express our choice of non-existence. But all of this is sustained by the only human life that has been called "the first-born of all creation" - Jesus, the only son of our maker. He carries us within himself along with every consequence of our sin or independent living. As the most responsible being in the whole universe he has committed himself to enduring whatever we do with our free wills.
Although there is no 'before' and 'after' in eternity, let's for a moment talk in simple terms. A millisecond after God had his only Son he made you and me inside his Son so that he could come to earth in the human race. This is the meaning of those words we quoted before from the book called 'Ephesians' - "we are God's workmanship created in Christ Jesus for good works which he has prepared beforehand that we should walk in them". In his son our creator works to complete his universe through us -- and bears all the negative consequences of our rejection of his life in us. Thus this present world is a temporary picture of what life was not meant to be: the creator himself bears the fatal consequences of all our autonomous actions so that we may be kept alive for a further opportunity to accept his life within us. God is no distant, impassive scientific experimenter observing us through a microscope -- he has put himself at risk and bears all the strains internally of his will and nature being assaulted by children whom he loves as his only son. This is the cost of making free-will beings and giving them every chance to make the choice between life and nothingness.