In this blast from the past, J. Warner Wallace examines the issue of 'heresy'. Are there any essential objective truths that Christians simply MUST accept if they want to call themselves 'Christians'? Are some Christian truths non-negotiable? Is anything 'out of bounds'? Are creeds necessary to protect objective truths within the faith? We address these important questions and answer listener email related to 'street evangelism' and 'environmentalism'.