The Apostle has written the Epistles first explaining the doctrine and then applying it to the saints in various churches. So the Epistles are divided between the indicative and the imperative. But the indicative is also taught in the imperative sections.The question is does the Apostle go from the indicative to the imperative without bridging the two usages of the law?  If you examine the text you will find that the Apostle bridges these two sections encouraging the saints to view life through the Psalms. Eph.5 19 Speak to one another with psalms, hymns and spiritual songs. Sing and make music in your heart to the Lord,"Col 3 16Let the word of Christ dwell in you richly as you teach and admonish one another with all wisdom, and as you sing psalms, hymns and spiritual songs with gratitude in your hearts to God.

Why does the Apostle bridge the two usages of the law by learning the Psalms?  He is teaching that living the christian life is more than knowing the doctrine and applying it. Is the christian life defined in scripture as two equal truths that stand side by side or is the apostle teaching that it is an orchestrated set of events that are created by God? We hear the drum beat that the christian life is two equal views of the law that stand side by side. The gospel usage and the second usage. We are saying that the bible teaches paradoxes.  "a situation, person, or thing that combines contradictory features or qualities" So we divide the truths of scripture in things that we can understand and things that are mysterious. These are explanations in order to make the scripture understandable. They are not in the text. When we view the christian life through the lens of paradox then we divide the truth into things that are clearly taught in the scriptures and the things that cannot be understood. If we try to explain the scriptures as a paradox then we are saying that outside of the historical teaching is "mystery."

The bible is not a book of paradox. Because paradox encourages us to explain the attach mystery to a truth that is not historically taught. But the bible encourages us to examine all of the words and learn each word usage as we question exactly what it means. If we teach that the bible is paradox then we are able to say that whatever we disagree with is a mystery. And we can be guilty of applying the scripture according to our philosophy of paradox by putting the mystery label on what is clearly taught. Some people will teach that Calvin taught this two line approach to scripture. But Calvin only mentioned it in passing. If we make a strong divide between the indicative and the imperative then we teach that both truths are equally valid. In this way we can teach in a philosophy that the validity of one truth contradicts the other truth. Or we can explain the gospel as a series of truths that happen in a process. But the apostle bridges the two uses of the law as a symphony that is created in using the Psalms.