A bent bow springs back, not merely to the perpendicular line, but bends to the opposite direction. A pendulum that is set swinging not only returns to the place from which it started but also swings as far in the other direction, and this is true of every great effort in life, whether intellectual or moral. After great intellectual strain, the mind returns, not to the condition of repose in which it was before, but to a condition of weariness. After great moral effort, there is danger of reaction, and this is especially true of penitence. After a great act of penitence there is a sense of joyous freedom from sin. The soul has been swept and garnished, swept by confession, garnished by the relief of knowing that it is not burdened any more. Yet this is only the negative side of spiritual life and is in itself a condition of unique danger. The old tenant has been driven out of the house. The house has been cleansed and prepared for a new tenant. A great victory has been won, but there is often a tendency to exaggerate the results of the victory, let down the defenses and think the war is ended when only one battle has been fought. The enemy may have been routed, but if we give ourselves up to mere rejoicing, the enemy may return with recruited forces and fall upon us while we are feasting upon the memories of our first victory, and so we may become an easy prey.
The flesh is not totally annihilated at conversion; the war goes on.
1 Peter 5:6-11
6 Therefore humble yourselves under the mighty hand of God, that He may exalt you at the proper time,
7 casting all your anxiety on Him, because He cares for you.
8 Be of sober spirit, be on the alert. Your adversary, the devil, prowls around like a roaring lion, seeking someone to devour.
9 But resist him, firm in your faith, knowing that the same experiences of suffering are being accomplished by your brethren who are in the world.
10 After you have suffered for a little while, the God of all grace, who called you to His eternal glory in Christ, will Himself perfect, confirm, strengthen and establish you.
11 To Him be dominion forever and ever. Amen.