When did God first plan to establish His Kingdom?
God first planned to establish His Kingdom from the very onset of the Old Testament, and especially after the call of Abraham, as part of the Abrahamic covenant where He promised to make Israel a special nation, give them land, and come to be their king.
Les explains that the Kingdom idea has been on God's mind from the very onset of the book itself, but especially after the call of Abraham. The Abrahamic covenant was between God and the nation of Israel: He would make them a separated, special nation, put them in a geographical area of land, and at the appropriate time come to be their king or set up the government. That comprises the Kingdom everything is looking forward to. In Psalms chapter 2, the format of prophecy is laid out: the rejection of the Messiah, then the tribulation, and then the Kingdom when God sets His king upon His holy hill of Zion, centered in Jerusalem.