Daniel 2:19

The writer narrated these events to help us understand that God revealed the mystery as a response to the prayers of the four men (cf. James 4:2). The answer came at night, but in a vision, rather than in a dream. In a vision, the person receiving the revelation was awake, whereas in a dream, he or she was asleep. Both methods were common vehicles of divine revelation at this time (Numbers 12:6). The writer waited until later to reveal to the reader what God had revealed. Here he wanted to focus our attention on the response to receiving this revelation.