These words of Jesus are so profound and full of truth that we would do well to take heed, for they serve as a warning for those who would be free. When we come to Jesus, with all our sin and the influence of evil rife in our lives, and give our hearts to Him, He does exactly what 1 John 1:9 promises. He cleanses us.
If we confess our sins, He is faithful and righteous to forgive us our sins and to cleanse us from all unrighteousness. (1 John 1:9 NASB)
In this passage, Jesus speaks to the maintenance of that cleansing. When He cleanses our hearts from all unrighteousness, it is our job to maintain that cleansing. The place unrighteousness occupied in our hearts will be filled with something. When we fill our lives with the Word of God and the fruits of the Spirit of God (love, joy, peace, patience, kindness, goodness, faithfulness, gentleness, self-control), there is less room for us to embrace the sin that would so easily entangle us.
A common problem, however, is that we come to Christ, confess our sins, experience His cleansing, and celebrate that freedom, then go back to the same lifestyle without any changes at all. We don't participate in Bible study, we don't read Christian literature, we don't become active in serving our Lord. Instead, we go back to the same habits, watch the same movies, read the same books, view the same websites. Before we realize what is happening, we have embraced the same sin that oppressed us before Christ. When we do this, the world looks on in disbelief, wondering what benefit there is to our faith.
Jesus explained that, when we experience His cleansing, the unclean spirits influencing us leave, (lust, greed, anger, unforgiveness, bitterness, etc). If we don't replace that influence with Him, the spirits/temptations to sin will return with even more spirits/temptations to sin, and we end up worse than we started. Perhaps you've seen someone who has come to Christ, had a glorious transformation that lasted for a brief time, then ended up with more sin and destruction in their lives than they had before Christ. It is a tragedy and all too common.
The only way to prevent this is discipleship. It is living the life of a disciple, committed to following Christ and becoming more like Him, that draws us toward righteousness and away from evil and sin. If we want to be free in Christ, we must not only choose it, but actively pursue freedom by our lifestyle choices. We cannot be a disciple of Christ and a disciple of the world.
It was for freedom that Christ set us free. (Galatians 5:1). If we want to live in that freedom, we must choose it, every minute of every day. We cannot continue to do the things that brought us bondage. It requires that we take every thought captive (2 Corinthians 2:5). When we begin to ponder our sinful desires, we take that thought captive when we choose to change our line of thinking to one that pleases Christ, whether by offering praise to Him, prayers for strength, or quoting Scripture.
In today's society, our focus tends to be on what "I" want, rather than what Christ wants. When I live my life to serve my wants and desires, however, I will quickly fill it with an incredible array of foolish choices that create a wasteland of my life. When I actively choose the life of a disciple, I will have less of the world (and likely less of those things the world holds dear) but I will also have more of the fruits of the Spirit, which is infinitely better.
Are we trapped again in the sin that held us before? Confession brings cleansing. Discipleship keeps us clean. Make a choice, then make the change that choice requires.
The question is simple. Do we want to be free of sin or not? If we want freedom, we must choose discipleship, for it is only by choosing to stay free that we can live free.