A Christian can lose sanctification, or the second work of grace. But, you may ask, wouldn't someone jealously guard such a precious gift? Often, Christians lose the blessing by refusing to testify of it. They may also lose sanctification if they allow the soul to become burdened again, or through deliberate disobedience or neglect.
Usually, the loss is not sudden. Rather, it's a gradual, slow leakage of joy, liberty, and power. For example, you may lack the deep, steady peace in your heart that you used to have. Instead of freely testifying, you feel afraid. At prayer meetings or in personal witness, your tongue is paralyzed. Or, when you do testify and pray, your words lack power.
Do you know the blessed peace and joy of this second work of grace? If so, do you jealously guard it? Or are you sensing it slowly leak away?