What is the relationship between the Old Testament and the spiritual kingdom?

The Old Testament contains many types and shadows that point to the realities of the spiritual kingdom fulfilled in Christ. As Mikal Smith notes, the Old Testament was an incomplete revelation, and the New Testament provides clarity and fulfillment. For instance, the ceremonial laws and practices find their true meaning in Christ's redemptive work. Hebrews 1:1-2 highlights this transition by stating that God spoke through the prophets, but in these last days, He speaks through His Son. The spiritual kingdom established by Jesus continues the narrative of the Scriptures, demonstrating that the faithful from the Old Testament were being prepared for the full revelation of the kingdom made manifest in the New Testament.