What does Daniel 7:28 mean?

Daniel has experienced an intense, disturbing dream (Daniel 7:1, 15). He needed the assistance of an angelic being to grasp the meaning of what he saw (Daniel 7:16, 19). As explained, his vision predicted a time of horrific persecution and conquest at the hands of a powerful empire and its blasphemous ruler (Daniel 7:7–8, 23–25). Fortunately, this time will be short and God will bring justice and judgment for His people (Daniel 7:26–27).

Although Daniel was deeply faithful to God, he was also human. His dream left him shaken and troubled. That his "color changed" implies becoming pale or flushed: both signs of emotional distress (Daniel 5:6). Prophecy gives believers much to think about. Some of what it reveals can be gruesome. Those who have put their faith in Christ should rejoice that these prophecies reveal the Lord's victory over evil. However, like Daniel, it's also reasonable to be unsettled over the violence and turmoil which are caused by evil.

The final sentence in this chapter indicates that Daniel "kept" this knowledge "in [his] heart." This may mean that he did not share what he'd learned with others, instead choosing to only write it down. This is consistent with some of God's prophetic messages, which are meant to be delivered and then kept for a later time. Some of Daniel's other visions, in fact, are described in this way (Daniel 12:4). It's also possible that Daniel means he worked hard to consider what he'd seen, striving to understand God's will (Luke 2:19, 51).

This verse ends the part of Daniel's book written in Aramaic (Daniel 2:4—7:28). During Daniel's life, this was the common language of the world. This suggests that what's recorded is meant as a message for the entire world, or at least as a warning to the non-Jewish nations. The rest of Daniel's writing is in Hebrew; its contents are more directly targeted at the people of Israel.