“[N]ot the thought of man’s welfare, but that of the glory of God was supreme in our Lord’s teaching concerning the kingdom. While emphasizing this, we must not forget, however, that to him this thought was inseparably connected with the idea of the greatest conceivable blessedness for man. That God should reign was in his view so much the only natural, normal state of things, that he could not conceive of any true happiness apart from it, nor of it without a concomitant state of happiness for those who give to God the first and highest place…. That God himself regards the kingdom in this light appears from the fact of his having prepared it for his own from eternity, Matt. 25:24.The preparation from eternity shows, that the kingdom is the supreme embodiment of the divine gracious purpose. Hence also the kingdom is said to be ‘inherited.’ Because the kingdom thus includes all that is truly valuable and precious, our Lord in connection with the kingdom parables pronounces the disciples blessed who see and hear the truth concerning it. In doing this they are brought into immediate contact with the fulfillment of all the Old Testament promises. What many prophets and righteous men in vain desired to see and hear, is theirs in actual possession, Matt. 13:16, 17.” (Geerhardus Vos,The Kingdom of God and the Church, pages 70–71).
Jesus has a somber warning near the end of Sermon on the Mount, but he also points you to the new life he offers in his kingdom.
Quote from the Reflection for Trinity Presbyterian Church, OPC