"The Kingdom of God" is the presence, the undivided, complete dominion of God's Laws, His Commandments, in Man as the highest manifestation of His creation.
"The Kingdom of God" is God's established reigning, ruling Will of God, His Laws and Commandments, handed down to the nations by the Patriarchs, Prophets, Christ, and Apostles, in all manifestations of Life.
"The Kingdom of God" is the true, righteous way of life of man and society, which is established on the knowledge and fulfillment of the Wisdom of God's Will, expressed in the Laws of His Commandments.
It is the highest moral and spiritual state of man's spirit and soul - when his thoughts, desires, feelings and righteous life, are established on God's Will, when man is guided in everything by His Commandments.
"The Kingdom of Heaven" is the state of man who has embodied in his righteous life the "heavenly," spiritually-exalted Truth, Will of God.
It is the blessed state of a righteous man, born of the Holy Spirit of Truth by the fulfillment of God's Commandments, reaching, gaining Eternal Life.
It is the comprehension of the Divine Will, which "descends" from "Heaven," that is, from the spiritual height of the Revelation of His Wisdom to the realization of it by man, who has manifested in himself the spiritual "Image" of the Son of God.
"The Kingdom of Christ" is the triumph of Righteousness, Peace and Love among people living according to Christ's teaching of the Will of God.
It is the Kingdom of the Holy Spirit of the Will of God as revealed in the Teachings of Jesus Christ and in the holy way of His Life.
"The kingdom of man" is the power, spiritual and physical dominion of man over man. It is power centered in the hands of one man or group of men, asserted through various systems of violence, and governed by appropriate laws which exercise and enforce its undivided dominion over all spheres of peoples' lives.
It is the existing system of man's sinful life, exercised by the undivided domination of destructive ideologies and his purely carnal interests.