Daniel 2 is a good example of how Jesus' teachings about the kingdom provide additional information not found in the prophets.
Most (if not all) Christians believe "the rock cut out of a mountain, but not by human hands" is Jesus Christ. "Not by human hands" is a fitting description of the One who was the Only Begotten of the Father, the virgin-born, Emmanuel, God with us. In "the rock cut out of a mountain, but not by human hands" we see the first coming of the Messiah when the Word was made flesh and dwelt among us.
We are told that "the God of heaven will set up a kingdom that will never be destroyed". Jesus taught that the Kingdom was "near" (Matthew 4:17), had "come upon you" (Matthew 12:28), and was "among you" (Luke 17:21). We see in Jesus' ministry the purpose for the rock being cut out of the mountain, in establishing God's kingdom.
Nebuchadnezzar saw that "the rock that struck the statue became a huge mountain and filled the whole earth". Through sayings such as the parables of the yeast and the mustard seed we learn that the growth and development of the kingdom is a process which has small beginings and establishes its presence without us being aware of any visible change. These are added details which were not revealed to Daniel, but may have been hinted at when Nebuchadnezzar saw the rock become a mountain (i.e. a process not an event).
Jesus struck the image 2,000 years ago (in the time of the fourth kingdom, as prophesied): when he "disarmed the powers and authorities, he made a public spectacle of them, triumphing over them by the cross" (Col 2:15) and "he led captives in his train" (Eph 4:8). The decisive blow in smashing the image was made at the cross, and the process of grinding the kingdoms of men to powder commenced then.
However, Christadelphians generally miss Jesus' teachings about the present reality of the Kingdom. They have an eschatology grounded in the Prophets but lacking the New Testament dimension.