When you witness you will run into those who profess to be Christians but show little evidence of being born again. When sharing with them, begin by using God’s Law to reveal the serious nature of sin against God. If they are not saved, it is likely they look at Christianity as a religion instead of a relationship with our holy God. However, once they see that their sins are against their Creator, this will make the gospel personal. They will see that religion and good works cannot appease God and understand their urgent need for His personal forgiveness.
Another simple approach to reveal where they stand with the Lord is to ask – “Do you believe Jesus is God Almighty, the Creator, the only sinless Savior?” I asked this question to a lady at an outdoor festival after she became upset with me for giving her The Good Test. She said she was a Christian, but told me it was wrong to do what I was doing. I ignored her objection and asked her if she believed Jesus was God – the only Creator and Savior. She was silent. She didn’t believe that. I then quoted Jesus’ words: “If you do not believe that I AM He, you will die in your sins.” She left quite convicted.
That day the Lord used His law and Christ’s identity to remove her false sense of security, and by His grace, she will yet come to repentance! Remember, we are commanded to warn all men, even professing Christians.