"For I am confident of this very thing, that He who began a good work in you will perfect it until the day of Christ Jesus."
"So shall My word by which goes forth from My mouth; It shall not return to Me empty, without accomplishing what I desire, And without succeeding in the matter for which I sent it." Isaiah 55:11
God has a word on your life and He will see it through until it is accomplished. God has a picture of you living fully in Him. That is what He is going for in your life.
Is there something you constantly struggle with? That area is what God wants to restore so you have total freedom in it. He has to take you through the stages from bondage to freedom. If He threw freedom at you when you're so used to bondage you might run right back to being jailed up. He prepares you. Think of the Israelites in the desert. It took time to get them released from Pharoah. God got them working harder, building them up physically. God got them in sync with Him emotionally and spiritually as each answer to prayer was seen. God has to dig out every tentacle of that imprisonment so nothing is left, so you are totally free.
I'm not talking about salvation here -- people can be saved in a moment. You just "confess with your mouth that Jesus is Lord and believe in your heart He was raised from the dead and you will be saved." (Romans 10:9)
But God doesn't stop at just saving you spiritually. He wants you to experience that freedom, that salvation in every part of your life. That is where the process comes in. That is why Believers aren't just like Jesus often -- God is still working on them.
Give God that area that is holding you back. Let Him do His stuff. It will be painful but so worth it. You will finally be free.