Why is it so important that we know the Word of God for ourselves instead of just listening to inspired teachers? Because any man besides Jesus Christ is able to make errors. I’ve made a few myself over the years. How will we know the information is not correct? By knowing the Word, by the Holy Spirit, and by checking it out after to ensure it is accurate. False teaching is increasing every day because the enemy knows his time is short, so we must be prepared.
Be sober, be vigilant; because your adversary the devil, as a roaring lion, walketh about, seeking whom he may devour: Pt. 5:8
I know that when I'm gone savage wolves will come among you and not spare the flock. Indeed, some of your own men will come forward and distort the truth in order to lure the disciples into following them.
Acts ,30 ISV
Paul knew we were prone to deception because he said, “you are all too willing to listen.” (2Cor. 11:3,4) and could be lured away from Christ. Our human nature only wants to listen to the things which make us feel good about ourselves, or are easy on our ears, but it is the whole counsel of God that will transform our lives by the renewing of our minds (Rom. 12:2).
"We must realize that the way to deceive people with counterfeits is to imitate the genuine article as closely as possible. For example, if counterfeiters want to pass off fake one-hundred-dollar bills, they do not print Donald Duck’s picture on purple paper. Instead they attempt to duplicate a true bill,” said Craig Hawkins. Deceiving teachers will come carrying a Bible, quoting Scripture and preaching a wonderful godly sounding message that will be very well received and popular. “believe them not, though they speak fair words unto thee.” (Jer. 12:6)
Now the Spirit speaketh expressly, that in the latter times some shall depart from the faith, giving heed to seducing spirits, and doctrines of devils; Speaking lies in hypocrisy… 1Tm. 4:1,2
Dear friends, stop believing every spirit. Instead, test the spirits to see whether they are from God, because many false prophets have gone out into the world. 1John 4:1 ISV
For example, there are teachers who teach God will forgive us if we sin so we can leave sin in our lives and still go to heaven. The Bible says:
Do not let anyone deceive you with meaningless words, for it is because of these things that God's wrath comes on those who are disobedient. Eph. 5:6 ISV
…some godless teachers have wormed their way in among you, saying that after we become Christians we can do just as we like without fear of God’s punishment…they have turned against…Jesus Christ. Jude 1:4 TLB
Don’t judge what you are hearing/ reading by the looks or reputation of the person (John ), or your perception of their skill or knowledge. Be as the Bereans and check it out (1Cor. ; Acts ). Follow the Spirit who helps you understand the Word, and will help you recall it (John ; ) when needed.
Remember:
"Let no man deceive you by any means…"
1Th. 2:3