God is reminding Habakkuk that what goes out of His mouth comes back to Him having fulfilled its purpose. God is not a man that He should lie. If God says something, it will be done, and done the way and in the time that He says it will be done.
John W. Ritenbaugh
Faith (Part 2)
First, God allays some of the prophet's fears by implying that what He has told him is not necessarily a revelation of doom and despair. It may seem that way, but ultimately, the vision is encouraging, hopeful, and glorious. This is why He instructs him to write it down plainly so people will understand it and be encouraged by it—and thus run.
Hebrews 12 contains a similar metaphor of running. Perhaps Paul had Habakkuk in mind as he wrote it, since he quotes Habakkuk in Hebrews 10:37-38. The apostle explains in Hebrews 12:1 that the race we run is our Christian lives. We can take the words of Habakkuk and run because we know that it all works out right in the end (Romans 8:28). Our Savior has already done His work, so if we finish our race, we will be saved. There is no doubt about this because He is not only the beginner of our faith, but He is also the finisher of our faith. So we can run with patience, just as God told Habakkuk to do. Even if it seems to tarry, patiently wait for it, because it will happen just as He has promised. His will will be done.
In Hebrews 12:5-11, Paul goes through a section on discipline, chastening, correction. This is what Habakkuk had just heard—that God would discipline, chasten, correct His people by the wicked hand of Babylon. Paul says in Hebrews that if God does not chasten us, we are bastard children! The chastening, though unpleasant, is for our good. We may not like the humiliation of it, but we can patiently endure it because it is for the best.
Our chastening is not a time to lag or worry but to strengthen ourselves through God and move forward because it is important that we endure and finish (Hebrews 12:12-13). When things get tough, the tough get going. Do not be like Esau (Hebrews 12:15-17), who had a great promise and inheritance and threw it all away for some temporary relief. We should never settle for temporary relief if it will knock us off the path! It is not worth it because it will end in bitterness, tears, disappointment, and failure.
Paul shows in Hebrews 12:28 how we should approach God, even when things do not seem to be going the right way. We must serve Him acceptably with reverence and godly fear, just as Habakkuk did. Yes, he questioned Him, but he said, "You are God, and You know something that I do not understand, so I will wait patiently. I will see this through, and then I will respond." If we do not approach God properly, we may find ourselves caught under the heel of the Chaldean with the sinners.
"That he may run who reads it" suggests a herald, like in medieval times, who went from place to place with a message from one person to another. God is instructing Habakkuk to put the revelation down clearly so that someone in the future can take it and deliver it into the right hands, those who need to hear it. Anyone in the end time who is speaking God's words fulfills this.
Richard T. Ritenbaugh