Just as industry has not discovered a material that will not stain or soil, neither has God created a life that is sin-proof. No matter what our station in life, we are vulnerable to sin. Preachers and deacons sin, members in the pew sin. Everyone sins. That's why Romans 3:23 says, "All have sinned and come short of the glory of God."
On wash day we apply every known technique to clean our clothes, often they appear to work, but sometimes need something stronger. The whites didn't get white enough, so we added Purex. A certain stain didn't completely come out so we worked on it longer. Then we realized that certain stains needed special solvents to remove them; then and only then were the stains removed.
That's the way it is with the Christian life. We are all sinners, people with stained and dirty spiritual lives that are constantly being washed by the Holy Spirit and dipped in the blood of Jesus."

As Christians, we are humbled by our vulnerability to sin. However, we are equally strengthened to know that there is no stain in our lives that the blood of Christ cannot remove.