What is the difference between permissive will of God and perfect will of God?

To start, God is sovereign. Nothing can get by Him or change His perfect will. However, we must acknowledge that humans (believers and unbelievers), were created by God to make decisions concerning basic life, needs and desires. Therefore, where does our choice fit in with God's will? This is a great question, but one that we will never fully understand this side of Heaven. 

God's sovereign will ensures that the outcome of mankind’s decisions conforms to His will in the end. Therefore, mankind possesses a free will to make choices in defining the path in life, complete with daily choices, Nevertheless, God's will sets the destination for our path, so that in the end we remain accountable for the path we chose. This would be considered God's perfect will, as Romans 12 confirms: 

ROM. 12:1 Therefore I urge you, brethren, by the mercies of God, to present your bodies a living and holy sacrifice, acceptable to God, which is your spiritual service of worship.
ROM. 12:2 And do not be conformed to this world, but be transformed by the renewing of your mind, so that you may prove what the will of God is, that which is good and acceptable and perfect.

Should we listen and apply this verse to our life we will find that everything we do with our body (mouth, eyes, ears, etc.) can be conformed to God's perfect will. Paul instructs us to not harmonize with or entertain the way of the world (unbelieving ways) but instead to renew our mind in the perfect word of God which then brings transformation in our lives, which is the manifestation of God's perfect will in a life. 

Regarding God's permissive will, let us first define permissive:

Granting or tending to grant permission – TOLERANT

With that definition we can clearly see that when a person depends on his own desires, rather than seeking the desires of God with our life or daily choices we are acting within the realm of God's permissive will. He is allowing the decisions we choose, for a time, but as we mentioned before God ensures the outcome of our decisions to meet His perfect will in the end. In other words, God is tolerant of some of our decisions that may not line up with His perfect will, but because God is sovereign in all things, He will even use our bad choices for His good, as scripture confirms: 

ROM. 8:28 And we know that God causes all things to work together for good to those who love God, to those who are called according to His purpose.

The greatest example of humans living within God's permissive will is in Genesis 3, at the fall: 

GEN. 3:1 Now the serpent was more crafty than any beast of the field which the Lord God had made. And he said to the woman, “Indeed, has God said, ‘You shall not eat from any tree of the garden’?”
GEN. 3:2 The woman said to the serpent, “From the fruit of the trees of the garden we may eat;
GEN. 3:3 but from the fruit of the tree which is in the middle of the garden, God has said, ‘You shall not eat from it or touch it, or you will die.’”
GEN. 3:4 The serpent said to the woman, “You surely will not die!
GEN. 3:5 For God knows that in the day you eat from it your eyes will be opened, and you will be like God, knowing good and evil.”
GEN. 3:6 When the woman saw that the tree was good for food, and that it was a delight to the eyes, and that the tree was desirable to make one wise, she took from its fruit and ate; and she gave also to her husband with her, and he ate. 

Woman knew God's prohibition, not to eat from the tree, but with her eyes she saw it was good, delightful and desirable, therefore she ate. We know this choice wasn't in keeping with God's perfect will but because He gave His bodily creatures the ability to make choices within His will, this is when His permissive will is at work. God is Sovereign over all, determining the end or the outcome but in the meantime we are left with decision making that is working within His permissive will at times. This is apparent when a believer submits to their own personal desires in decision making rather than surrendering and seeking the Father's plan. We are all given choices every single day of our lives. Are they glorifying Christ or are they for personal gain? 

As a believer we all are in Christ: 

ROM. 6:11 Even so consider yourselves to be dead to sin, but alive to God in Christ Jesus.
ROM. 6:12 Therefore do not let sin reign in your mortal body so that you obey its lusts,
ROM. 6:13 and do not go on presenting the members of your body to sin as instruments of unrighteousness; but present yourselves to God as those alive from the dead, and your members as instruments of righteousness to God.
ROM. 6:14 For sin shall not be master over you, for you are not under law but under grace.

Here Paul explains that because we share in the death, burial and resurrection to new life, through Christ, we no longer are slaves to our sin nature; we have a direct lifeline to do the perfect will of the Father, through the leading of the Holy Spirit. But when God allows us to detour from that path, we are then living out the permissive will of the Father. 

We suggest doing the Sovereignty of God series, or listening to our Romans Teaching to better understand this hard concept.

Scripture quotations taken from the (NASB®) New American Standard Bible®, Copyright © 1995, 2020 by The Lockman Foundation. Used by permission. All rights reserved. www.lockman.org