There are still many people in our society who believe themselves to be Christians in right relationship with God and headed for heaven. To diagnose their faith and see if they really understand the Gospel, ask them a question that will reveal the basis for their feeling of security. The second diagnostic question of Evangelism Explosion is a great one for this: 'If God were to ask you, "Why should I let you into my heaven?" what would you say?'

Many people will answer that they do their best or that they try to be good, or they refer to involvement in their church. All of these answers reveal that this person really doesn't understand grace, but rather they think that they must earn heaven. This gives you a good starting point to talk about grace, "for all have sinned and fall short of the glory of God, and are justified freely by his grace through the redemption that came by Jesus" (Romans 3:23-24)