If a Christian desires to maintain purity in his or her beliefs, with no compromise, the following things must be avoided. This is not to be taken as legalism; it is maintaining a life consistent with what one believes and living a sanctified life, as commanded in Scripture.
I and II Timothy, and Titus, talk about errors to avoid in teaching. We are to make no apology for our beliefs, not be ashamed, and we are to rebuke and correct.
I Timothy 1:4 says that "endless genealogies" are to avoided. Isn't this a fitting description of the Mormons? We are also to avoid "fruitless discussions" (l:6), anything "contrary to sound teaching" l:10), "deceitful spirits and doctrines of demons" (4: 1), and a "morbid interest in controversial questions and disputes about words". (6:4)
II Timothy mentions "wordly and empty chatter" (2:16), and says to "refuse foolish and ignorant speculations". (2:23)
In Titus 1:10-11 we read that "Rebellious men, empty talkers, and deceivers must be silenced because they are upsetting whole families." We are also told in 3:9 to "Shun foolish controversies and genealogies and strife and disputes about the Law" which are "unprofitable and worthless."
Hebrews 13:9 says, "Do not be carried away by varied and strange teachings."
THE FOLLOWING PRACTICES AND ASSOCIATIONS MUST BE AVOIDED
Astrology, transcendental meditation, altered states of consciousness, speaking in tonques as a requirement for salvation, free masonry in all of its forms, including DeMolay, Job's Daughter's, The International Order of Rainbow for Girls, taking blood oaths, Harry Potter, saying the Lord's Prayer backward, communion using animal blood, ouija boards, the table game "Dungeons and Dragons", and any type of animal sacrifices, heavy metal music with Satanic lyrics, Satanic or occultic TV shows, movies, and video games, Temple of Set, and repeating mantras.
BOOKS TO BE AVOIDED
There are so many books that it would be impossible to list all of the ones to avoid. You must have convictions based on biblical teaching and then judge all other books in accordance with your beliefs.
PEOPLE TO AVOID
Just like the books, there are too many individuals teaching doctrine contrary to what the Bible teaches. You must know your beliefs and stand by them.
Don't get involved in any organization, give money to, or identify with any person, unless you know that their teaching lines up with biblical doctrine and is consistent with core Christian beliefs. In other words, one cannot be a true professing Christian and, at the same time, be involved in any of the things mentioned above, because their core beliefs are diametrically different than those of Christianity. These are all man-made philosophies or religions, and they are not based on the core Christian belief of the resurrection of Jesus Christ.
It is also helpful to know specific symbols, terminology, and logos like the Rainbow Flag, which is a symbol of the homosexual community, and a flag with a cresent moon and a star, which represents Islam. One must also keep in mind that the phrase "born again" means different things to different religious sects. It is important to know what the word "karma" means and what a "guru" is. If you do not know the significance of these and other words used in human philosophies and cultic thinking, do some research on the internet.
Be very careful who or what you identify with, or you may be compromising your core Christian beliefs and principles.