These are words that are used to describe an attitude that refuses to bend to the power of another. There are times when being defiant or immovable is good and there are times that it is bad. Early Christians refusing to bow before the Emperor - Good. Followers of God refusing to listen to scripture - bad.
One is seen as strength the other as weakness. One makes you feel weak when you are not and the other makes you feel strong while you are weak. It is a condition that every human being on the face of the earth will have to deal with at one time or another. We can (and often do) become extremely willful in our lives and turn off all reason in the process.
God often referred to the stubborness of his people as being "stiff-necked" when they would desert their commitment to Him and chase after phantoms of pleasure or power. It was something that would draw the ire of the Most High more than just about any other attitude.
In Psalm 32:8-9 God tells us this:
I will instruct you and teach you in the way you should go;
I will counsel you with my eye upon you.
Be not like a horse or a mule, without understanding,
which must be curbed with bit and bridle,
or it will not stay near you. (ESV)
God understands us and thus, knows that we are going to become willful as He leads us. He warns us against it. Notice the imagery.
Don't be like an unthinking horse or mule. This is what I meant when I said being stubborn and refusing to listen to God's voice in the scriptures can make you feel strong when you are in truth being incredibly weak. For God, (Creator of Everything!) being willful against Him means we have reduced ourselves to the level of creature rather than the pinnacle of creation that displays God's image. When we think we are exercising strength we are really disengaging from what really matters.
Because apart from God, man has no reason for existence. Humanity was created to bring Glory to God by revealing His nature, His love, His wisdom, and His Holiness. When we are defiant, we are refusing the very things that are meant to define us. Without them, Humanity becomes something less than it was intended to be by its Creator.
God does not want to force us to listen or obey. That's what we have to do with mules and horses. We have to force them. God created us for more. Notice the promise of these verses. "I will instruct you and teach yo in the way you should go. I will counsel you with my eye upon you."
God has told you that you aren't in this alone. He wants to walk your journey with you and He promises to equip you for what you need and for where you are going. He says He will keep His eye on you like a father watching carefully as his son learns to handle a power saw or shoot a gun for the first time. His eye is there for protection and guidance into becoming more than you were before.
It is a promise from your Father.
Yet, this is the tragedy of becoming stubborn, hard-hearted, or stiff-necked. We are refusing the help of the Father who loves us. We are refusing the One and ONLY One who can lead us where we need to go. Instead, we tell Him "I got this."
Every time man has said this to God, something very bad has resulted, which leads us to the conclusion of Psalm 32. Verses 10-11 lay it out for us:
Many are the sorrows of the wicked,
but steadfast love surrounds the one who trusts in the LORD.
Be glad in the LORD, and rejoice, O righteous,
and shout for joy, all you upright in heart!
It isn't that God decided to make your life miserable because you didn't do what he wanted. Rather, it is the natural state of affairs. When we become stiff-necked, we rebel against all sound judgment. We refuse the hand of the Loving Father and we hurt ourselves, again, and again, and again.
For those who will listen to the Father, bend their will to Him and seek Him, the steadfast, protecting, guiding, watchful love of the Father will be in your life. Its not that you won't make mistakes. It is that the Father will be there to keep you from hurting yourself and stop you before you really do something foolish. His love will protect you from yourself. When we become stubborn we refuse his help. When we are willing to listen, His Love surrounds us and will not need to fear the valley of the shadow of death.