According to Thomas Watson, the Kingdom of God is two-fold – the kingdsoms of grace and glory. The Kingdom of Grace (Rom 14:17, Luke 17:21) is God’s drawing men to Himself out of the Kingdom of Darkness (Rom 6:12, Col 1:13, 2 Cor 4:4, Acts 26:18). The Kingdom of Glory is consummated at Christ’s return. The Kingdom of Grace is the beginning (the seed) and the Kingdom of Glory is the End (flower).
The kingdom of grace, [is that] which God exercises in the consciences of his people. …When we pray, ‘Thy kingdom come,’ we pray that the kingdom of grace may be set up in our hearts and increased. We pray also, that the kingdom of glory may hasten, and that we may, in God’s good time be translated into it. These two kingdoms of grace and glory, differ not specifically, but gradually; they differ not in nature, but in degree only. The kingdom of grace is nothing but the beginning of the kingdom of glory. The kingdom of grace is glory in the seed, and the kingdom of glory is grace in the flower. The kingdom of grace is glory in the daybreak, and the kingdom of glory is grace in the full meridian. The kingdom of grace is glory militant, and the kingdom of glory is grace triumphant. There is such an inseparable connection between these two kingdoms, grace and glory, that there is no passing into the one but by the other. …Many people aspire after the kingdom of glory, but never look after grace; but these two, which God has joined together, may not be put asunder. The kingdom of grace leads to the kingdom of glory.
Watson, Thomas. The Lord’s Prayer, Chapter 7, “Thy Kingdom Come”