Even the unfallen angels of heaven must veil their eyes before the glory of God and His eternal righteousness. Thus the truth of justification by faith in Christ shall be a lesson which remains throughout eternity for all of the created beings in all the universe. These are not lessons that one learns in one day, but rather the truth must be learned through many bitter lessons of agonizing conflict and struggle with our sinful stubborn will and nature. The lesson of Romans 7 is the lesson of a life-time and it is for this reason that God in His infinite wisdom does not completely remove the old sinful nature from the believer. The hard old soil, as an allegory of the fallen human heart, would now require sweat and toil to pull up the weeds and the tares and this would require a lifetime of discipline and patience and diligence and perseverance through repentance towards God and faith in His redeeming imputed grace.
Character is developed in the school of affliction and the furnace of the fires of hardship.
We are to be students in this school for a life-time. Only the wisdom of our eternal Father could have devised so complete a salvation for the fallen sons and daughters of Adam. In this life there is hardship and tears, but by taking up our cross and following our great exalted Head we will be lead out of this valley of the shadow of death and one day stand on the sea of glass before His throne. There we will cast our crowns down before Him and declare that we are unworthy to be there. This is the song of Moses which no man can sing but those who have come out of great tribulation and washed their robes white in the blood of the Lamb.