The Ages of Mankind
At Isaiah chapter two, this prophet began at verse two to reveal a Divine plan that would mark the beginning of the last days. It would be at this time that what Isaiah referred to as "the mountain of the Lord’s house" would be established in the tops of the mountains and exalted above the hills. He described such a house of the Lord as being that unto which all nations would flow, and that all would be taught of the will of God.
The period of time to which reference is made is the dawn of the Christian age, in which the will of God is revealed from the first age of man’s history, during which God dealt with man through the patriarchs, or the heads of families, households, or nations.
It was later, in the second such period of man’s history, that God would deal with man through Moses, by whom He gave His law. It is the third and final such age, which Isaiah refers to as " the last days", that God would make known His will through Jesus Christ.
The opening of that age was marked by the establishment of the Church, to which Isaiah referred as "the mountain of the Lord’s house." While the temple in Jerusalem was situated upon a hill, and was recognized as the very center of Israel’s worship and religion, the Church of the Lord was to be considered exalted much more highly than even that temple, though not in strictly geographical terms. Rather, the exaltation of the Church was based upon it’s unsurpassed spiritual value as the blood-bought property of it’s Savior and Head, Jesus Christ.
Although Israel had been accustomed to sharing it’s religion with only those who were the seed of Abraham, Isaiah prophesied of the Church as being that which would be intended for all nations of the world.
So profound an effect did this concept have on the Jewish nation that Paul in Ephesian epistle described the bringing together of all the world’s peoples into one spiritual body as a "mystery". Regardless of the hesitancy of the world to accept and adopt the Lord’s master plan for His Kingdom, this would remain a principle of that Divine will which Isaiah declared would go forth from Heavenly Zion, the new Capitol of God’s chosen people, Heaven.