This is the message we have heard from him and declare to you: God is light; in him there is no darkness at all. If we claim to have fellowship with him yet walk in the darkness, we lie and do not live by the truth. But if we walk in the light, as he is in the light, we have fellowship with one another, and the blood of Jesus, his Son, purifies us from all sin. 1 John 1: 5-7 (New International Version)
The community to which John writes has been infiltrated by corrupt teachers. These individuals have twisted the Gospel to human desire, and made salvation a "spiritual" rather than a transformative experience. The Apostle challenges this notion not just from the perspective of apostolic preaching, but also the reality of who God is. Namely, our God is a God of Light, and in the Light of life He has redeemed a sinful humanity.
Sin can never be an accepted way in the life of a believer. While, on the one hand, it is true that we will still sin, because salvation does not sanctify us completely; on the other hand, through God's Spirit we are in a state of being perfected and must do our best to follow the example of the Master. Humility and obedience are the new defining characteristics of God's children, lived out in service to neighbors around us in love.
The danger for the church of 2020 is that we allow this "ear itching" teaching become a defining reality in our midst. More people than ever claim a "spiritual" relationship with Jesus, while having outright disdain for His body. These are polar opposites of the call of the Gospel. When we respond to Christ's invitation to faith we are to become a new creation, set on a lifelong pilgrimage toward the Kingdom established by our Lord and Savior.