Eventually the Lord appears to Habakkuk and commands his servant to write the divine answer on a tablet (v. 2). There seems to be a reminder in this method of how God gave his law and other matters to Israel centuries before at Mount Sinai, which would be a reminder that the Lord had not changed the righteous requirements he delivered to his people when he made a covenant with them.
Habakkuk was to write it clearly so that a messenger, who was assigned to go somewhere with the message, would not have to stop and study it because it was difficult to decipher. I suppose we have here an illustration of how careful the Lord’s servants should be in making clear what the Lord has said. The answer that Habakkuk would receive was not designed only for his personal benefit, but was also intended for the benefit of other believers.
The message states several important doctrines which the Lord wanted his servant to absorb and then pass on to others. Here are two such doctrines. First, Habakkuk receives a reminder about the sovereignty of God. There is an appointed time (v. 3), even if its fulfilment seems slow. If the Lord is referring to the appointed time of Babylon, then the fulfilment would not occur until the end of the seventy years’ captivity in Babylon. Nevertheless the Lord’s timing would be followed, no matter what the plans of the Babylonian rulers were.
Second, Habakkuk is reminded about the Lord’s knowledge of the heart of his enemy. God is fully aware that the soul of the Babylonian leader is proud and sinful, and that he is marked by unrighteousness (v. 4). Later in the chapter God will spell out his knowledge of the Babylonian leader to Habakkuk. At least, this means that God’s intention to use Nebuchadnezzar was not based on ignorance of his character.