Q Does being sanctified mean I have "arrived " spiritually ?
A Sanctification and arrival are not synonymous, but sanctification does mean that God has made us dead-in-earnest about becoming better persons. We must allow ourselves time to mature - like plums. A green plum may be a good green plum, but not good in the sense of being ready to eat. Also, horticulturists are constantly working to develop better plums, so a ripe plum today may not taste as good as a hybrid species twenty years from now.
Q How should my life be different after I have experienced entire sanctification ?
A Paul tells us in Galatians 5:22-23: "The fruit of the Spirit is love, joy, peace, patience, kindness, goodness, faithfulness, gentleness and self-control" (NIV). Expect these spiritual products to mature in you. But do not plan to pick ripe plums in February. Notice, for example, the peace of God in a ripened saint and the restlessness in a younger Christian. Or observe in an older member the ability to shoulder responsibility. He knows how to exercise stick-to-itive faithfulness even under the most-difficult circumstances. Observe the gentleness in a person who has lived long enough to know that everything doesn't come easily, that blame cannot be assigned naively, and that religious experience does not do the same thing for everybody.
Sometimes I think patience is the hallmark of the sanctified person. The genuinely Christian person lets others and himself learn the lessons of life at God's own rate.
Q Is sanctification a climactic event or a gradual process of growth ?
A Both. A United Methodist bishop, when reading the disciplinary question to ordinands, "Are you going on to perfection?" adds, "If not, where are you going?" The person who has made a definite decision to receive God in His fullness and who maintains that earnestness, has indeed experienced a climactic event and will strive for perfection.
How do we go on to perfection? First, by practicing the Christian disciplines: private prayer, public worship, fasting, study of God's Word and solid devotional material, the Christian friendship, and so forth. Ask yourself, Have I established holy habits? If not, ask God to show you His tailor made pattern for your life (imitating others leads to frustration, like wearing shoes that don't fit). Ask God for the gift of discipline; He will give it to you if you mean business. Seek the counsel of a mature Christian, perhaps someone on your pastoral staff or a church member. Sharing with someone will help you clarify your thinking; we never fully know what we think until we say it out loud.
A second way we go on to perfection relates to our behavior. Put feet to your faith and watch God's grace activate. John Wesley asks point blank, Are you touchy?
If so, deal with your feelings by frontal attack. Deliberately speak nicely to the person who hurt you, pray for him, do a favor for him. Victory lies in aggressive, faith-honoring action and documents God's active, sanctifying grace in your life.
Q Is it possible to lose sanctification ?
A Yes, of course. Suppose I renege on the Christian disciplines. Unless, for example, I suffer extenuating circumstances such as prolonged illness, termination from the public means of grace will naturally deflate my enthusiasm and earnestness for God and His kingdom. A vivid example: far fewer couples who attend church regularly (compared to those who do not take worship seriously) go through divorce.
Now, here lies the subtle factor in all this: we easily slide into a salvation-by-works way of thinking. We reason, If I go to church, say my prayers faithfully, and do good deeds, I will stay set apart for Him and grow in grace. And here we see the fatal error that Martin Luther exposed. True communion lies in openness to God; our works become the natural product of fellowship with the Divine. This openness to the Spirit saves us from hopelessness and debilitating pride and allows God to continue the work He began in us.