The main debts whose payment God demands are those which lie at the root of all right, those we owe in mind, and soul, and being. Whatever in us can be or make an adversary, whatever could prevent us from doing the will of God, or from agreeing with our fellow—all must be yielded. Our every relation, both to God and our fellow, must be acknowledged heartily. Smaller debts, if any debt can be small, follow as a matter of course.
If the man acknowledge, and would pay if he could, but cannot, the universe will be taxed to help him. If the man accepts the will of God, he is the child of the Father, the whole power and wealth of the Father is for him, and the uttermost farthing will easily be paid. If the man denies the debt, or, acknowledging, does nothing toward paying it, then—at last—the prison! God in the dark can make a man thirst for the light, who never in the light sought but the dark. The cells of the prison may differ in degree of darkness; but they are all alike in this, that not a door opens but to payment. There is no day but the will of God, and he who is of the night cannot be forever allowed to roam the day; unprized, the light must be taken from him, that he may know what the darkness is. When the darkness is perfect, when he is totally without the light he has spent the light in slaying, then will he know darkness.
by Earle Canty
The principle being taught is that, as Christians, we have obligations to God and to our fellow man, particularly our brother or sister in Christ. God has called us to live a certain way and to do certain things, one of which is doing His will. We must continuously seek Him and His will for our lives. Knowing His will for our lives, we must submit to His will, even when His will is not what we would naturally choose.
Debts owed to others must be acknowledged and paid. God’s will for our lives is that we repay our debts. No one living in accordance with God’s will should ever borrow from another intending to not repay the debt. The first step is to acknowledge the debt; without acknowledgement, nothing will happen. Failure to acknowledge the debt has a consequence – prison. This is not necessarily a literal prison; it can be, but it will certainly be prison-like on the mind of the debtor. No matter where the debtor goes or what the debtor does, the debt will be like a ball and chain attached to the debtor. It will be a constant reminder of what has been done. Failure to repay an acknowledged debt has the same consequence – prison.
This prison is a dark place, and to exit requires payment. Whether we like it or not, man often learns best by experiencing darkness and failure. We can be very unteachable when we don’t want to be taught (i.e., acknowledge that there is something to learn) or we don’t want to accept the consequence of our choice (i.e., we have a debt to repay). In either scenario, we are living in darkness, even though we may not be in a literally dark place. That is not God’s will for us, but it can be the way He gets our attention and gets us to live in accordance with His will.