“3 As I urged you on my departure to Macedonia, you should stay on at Ephesus to instruct certain men not to teach false doctrines 4 or devote themselves to myths and endless genealogies, which promote speculation rather than the stewardship of God’s work, which is by faith.” -1 Timothy 1:3-4, BSB
False doctrine is the teaching of myths, which is composed of a make-believe reality built upon lies concerning spiritual things like how to obtain salvation and the afterlife.
If you are motivated by speculation with things that are not in the Bible, which is capturing your attention, and with how important is one’s pedigree, you have drifted away from doing God’s work, engaging in false doctrine with the potential of being deceived.
Demonic spirits will always try to get you to go to another source, apart from the Bible, for spiritual insight.
The words in red are my comments and the words in black are the Scriptures.
1 Now the Spirit [the Holy Spirit will only lead you into God’s Word] expressly states that in later times [before the rapture] some will abandon the faith [the Word of God] to follow deceitful spirits and the teachings of demons [through other sources], 2 influenced by the hypocrisy of liars [who are false Christians being used by demons], whose consciences are seared with a hot iron. – Timothy 4:1-2, BSB
Friends, no other Book out there like the Bible is infallible. Every other source that tries to teach you spiritual truths might bring with it spiritual landmines. One wrong move and you can blow up your faith by substituting biblical truth for a lie. The immediate effect will be like a leech attaching itself to one’s faith, to drain it until it is all gone. That is what false doctrine does to a person who accepts the lie as the truth.