God has given you a new nature when you were made a new creation in Christ. He has given you a new heart. This means you have His nature in you. Hard to believe but it is true. I have given you a new heart and put my Spirit within you. The old has passed and the new has come. So why is it that we still operate in our old self? This is because we stopped believing in His promises. We need to continuously walk in His presence to experience His nature. We can choose to walk in the flesh or in the Spirit. When we walk in the flesh, the old feelings and thinking operate. In the new, the new nature operates. This is why you find that when you walk in the Spirit the new feelings and thoughts come alive. We are called to walk in the Spirit all the time not sometimes! How can one do this unless there is total surrender to Him? As long as we are in the flesh we will be tempted to walk in our old ways. This is where discipline and constant battle with the flesh and the devil occur. But when you walk in your new nature the flesh has no attention at all. The devil can’t touch you when walk in the Spirit. The key is to be filled daily in the Spirit and to walk by the Spirit.
I worked as a Consultant Psychiatrist in UK and Australia for over 40 years.