1. Without acknowledging freedom of the created person, God would be the origin of all evils and thus a hyper-demonic being: Each metaphysics, which denies the freedom of humans and of angels, and more precisely the abuse of freedom, as source and first cause of all the manifold evils that obviously exist in the world blames these evils on God or, if he is an atheist, on an unfree natural cause. In either of these two cases moral evil would not exist at all in humans. Because if humans and angels were determined to be evil, they would be innocent like lambs or like puppets; God, however, as long as his existence is not altogether denied, as the source of all evil and suffering, would be himself evil. Therefore each denying of human and angelic freedom either leads to atheism or to polytheism, or to a transformation of God into a super-demon (infinitely more terrible than Satan, because all evils from the beginning to the end of the world would be God’s fault alone, which cannot be said of Satan. In contrast to Satan’s limited causal role regarding other evils besides his own). If man and angels were not free and if therefore, granted his existence, God had brought into the world all meanness, all lies, all adulteries, all perjuries, rapes, murders, thefts, tortures, hate and envy, genocide and other crimes (including Satan’s and his angels’ sins) or if He had determined angels and humans to commit them, He would be the only ultimate source of evil (which cannot be said of Lucifer). One cannot imagine a more terrible destruction of the idea of God. God would be an Anti-God. In this case, Ivan Karamazov’s rebellion against God as responsible for all evils would be wholly justified.
2. Without divine freedom there could not be any contingent world and particularly no created free person: The origin of non-necessary beings in the world, and particularly of created free agents, could not be explained without creation being a free act of God, because a contingent and temporal world cannot proceed from God by a necessity rooted in the eternal and necessary divine nature but only from a free divine choice, and even more clearly: never could unfree causes in nature or in God explain the wonder of a free will in finite beings. Freedom in the world can come into being only from a free act of the absolute Being. Therefore, if God were not free, neither the contingent (non-necessarily existent) world nor free agents in it could exist. Therefore, do deny God’s freedom of choice, still retaining His existence, will lead to some form of pantheism that dissolves human personhood and freedom. Moreover, if the world and even evil flows necessarily from God, God would, if not freely, so necessarily, become the cause of evil as well, as Schelling suggests in his thesis that everything flows with absolute necessity (at least moral necessity) from God.
3. Without divine freedom there would also be no divine holiness: Each adequate idea of God implies His freedom also for another reason: as the condition and origin of His justice, mercy, and Holiness as the highest perfection of any person qua person: Without God’s supremely perfect freedom the core of divine perfection would be null. God would no longer be just, merciful and holy, and hence not God.
4. By denying divine, angelic and human freedom the entire Judeo-Christian revelation is being denied and Holy Scripture rendered a worthless book:
Without freedom, God would not be our creator, nor our redeemer, nor would there be divine forgiveness of sins, nor any reason for gratitude towards God for our creation, redemption or for the forgiveness of our sins, because if these were not works of divine free choice, they would be nothing.
Likewise without freedom of God, of angels and of humans all anthropological contents and teachings of Sacred Scripture and of the Church would lose their foundation: We would not be creatures but some moments in a necessarily self-unfolding life of God. There would be no original sin, no personal sin, no redemption from them, no meaning of the divine commandments, nor of any divine promises. The Sermon on the Mount and the call to holiness would not have any sense any more let alone eternal rewards or punishments. All talk of a purgatory, of moral conscience, of the sacraments of confession and baptism or the unction of the sick would be senseless babbling.
In a word: without freedom no Christianity! And also no Judaism and no Islam which recognize many of the same truths about God and man!
Therefore hardly any truth is more important not only for the metaphysics of the person and our personal life, but also for the Christian and any other theistic faith than this one: that the person, whether human and finite or divine and infinite, is free.