The simplicity that is in Christ. 2 Cor. 11:3.
Simplicity is the secret of seeing things clearly. A saint does not think clearly for a long while, but a saint ought to see clearly without any difficulty. You cannot think a spiritual muddle clear, you have to obey it clear. In intellectual matters you can think things out, but in spiritual matters you will think yourself into cotton wool. If there is something upon which God has put His pressure, obey in that matter, bring your imagination into captivity to the obedience of Christ with regard to it and everything will become as clear as daylight. The reasoning capacity comes afterwards, but we never see along that line, we see like children; when we try to be wise we see nothing (Matthew 11:25.).
The tiniest thing we allow in our lives that is not under the control of the Holy Spirit is quite sufficient to account for spiritual muddle, and all the thinking we like to spend on it will never make it clear. Spiritual muddle is only made plain by obedience. Immediately we obey, we discern. This is humiliating, because when we are muddled we know the reason is in the temper of our mind. When the natural power of vision is devoted to the Holy Spirit, it becomes the power of perceiving God’s will and the whole life is kept in simplicity.