A spiritual Kingdom includes all the aspects of a kingdom. 1 Peter 2:19 states, "You are a chosen race, a royal priesthood, a holy nation, a people who are God’s own possession. You have become this people so that you may speak of the wonderful acts of the one who called you out of darkness into his amazing light."
Jesus taught us to pray "Thy will be done on earth as it is in heaven." - Matthew 6:33. So, the question is what does this look like in business, education, relationships, families, investments and "everything our hands find to do."
When we do all these things as "unto the Lord," we build Kingdom. in a real, and practical way. The Kingdom is real and on earth, in us, right here and now. (Luke 17:21).