God created Adam with a HUMAN NATURE that seminally and therefore actually contained every possible human being ever to be born. It was part of his NATURE as Created by God. Human nature in Adam contained all possible human beings in seminal form. There was not a time Adam existed that all humanity in seminal form did not also exist as they were inseparable from HUMAN NATURE. Mankind was created to be polyanthroporism - many humans. Thus every individualized "seed" of Adam is EQUAL IN NATURE to the nature of Adam. Adam was HUMAN in nature and every "seed" in Adam is HUMAN in nature. Thus, Adam was IN UNION with all his posterity from the time he was created. However, such is not true concerning God the Son. At no point in eternity before Creation did anything exist in SPIRITUAL UNION with God or any Person of the Godhead other than the other Two divine Persons. At no point in eternity past did any "seed" exist seminally "in" God the Son. If any "seed" had any seminal existence in union with the SPIRIT NATURE of God the Son they would be EQUAL in NATURE to God the Son and thus polytheism would be the necessary conclusion. We are partakers of the divine nature due to creative restoration to the divine IMAGE in regard to CHARACTER or LIKENESS (Eph. 4:24; Col. 3:10) not by partaking of actual substance of Divine nature. We are also sons of God by ADOPTION (legal sons). God cannot actually impart his own Being/substance without making other god's. God can impart his own "image" or divine moral and rationale likeness and that is how we are made partakers of the divine nature through regeneration. We are united to Christ by regeneration - meaning - He exists within our human spirit as His dwelling place - not that our human spirit has undergone a transformation that actually mixes together as one substance human spirit and divine Spirit. There are plenty of texts that declare Christ has a "seed" but not one of these texts teaches this "seed" was in "spiritual union" or seminally within the pre-creation NATURE OF GOD. There are plenty of texts that teach we were in spiritual union with Christ before the world began in regard to PURPOSE/PLAN but not one in regard to actual pre-creation existence. None of the children of God were actually united to Christ until they were actually "created in Christ Jesus" in time and space. None were actual partakers of the divine nature until regeneration. Previous to physical and spiritual birth there was no ACTUAL or REALISTIC existence of the promised seed in any form whatsoever other than God's MIND just as there was no actual or realistic creation before creation other than in God's MIND. The seed of Christ existed in eternity past in the very same exact sense as creation of this world existed in eternity past. We were in spiritual union with Christ in eternity past in the very same sense we were glorified in Christ in eternity past. We were not condemned in Christ in eternity past exactly the very same way we were glorified in Christ in eternity past - not one iota of difference.