Be careful in the way the Bible is used, either by the cultist or by yourself. Consider the context, is a good rule. Be sure to see if the meaning of the passage has been modified by the cultist. Beware of those who quote Old Testament verses and try to apply them to First Century or Modern Churches or Christians. Share your personal testimony.
Cultists place great value on personal experience.
Express your personal faith in Christ. Tell of your personal spiritual experience. The more you can use in your testimony the terms that have special meaning to the cultist, the more the Holy Spirit can use it for His purposes. Share your faith in words designed to reach the cultist. Stress your assurance of salvation with the millennial groups, for they have little confidence in that area.