"CONTEND FOR THE FAITH", Jude 3, is a command, not a request. But it is to be done in the light of bringing the soul to Christ, NOT just to win an argument. Walter Martin used to say, "Argument for argument's sake is sin. Arguement to win the soul, is a divine command." Here you will find some of the resources that I have found most helpful when witnessing for Jesus with those who have been deceived by the cults.
THIS BOOK IS THE definitive work on this subject. Revised from the earlier edition written by the late Dr. Walter Martin, this work is a deep well of great information on all of the major religious movements of today.