1 Corinthians 4:6 I have applied all these things to myself and Apollos for your benefit, brothers, that you may learn by us not to go beyond what is written, that none of you may be puffed up in favor of one against another.
The key point of 1 Corinthians 4:6 is the dependent clause, "that you may learn not to go beyond what is written." Today, as throughout history, there are people and spiritual beings who would change the word of God, add to it, or cause it to be doubted, sincerely thinking they are speaking truth or insincerely trying to deceive (Genesis 3:1-5; Matthew 4:1-11; Revelation 22:18-19). In the Corinthian church conflict and division was being caused by people who were going beyond what is written and causing division in the Body of Christ and leading the people into error. Paul used what is written to correct error.
Today, we need to learn the word of God so we will not be carried into error by human experience and imagination and by spiritual deception. How gullible we humans are is revealed by the uncritical acceptance of the book and movie, Heaven is For Real. It is not scripture. It does not clarify scripture. It adds to scripture from human and spiritual imagination. I read the book and found at least 8 scriptural errors - some going beyond scripture and some contradicting scripture. I spent three hours reading the book. Many millions of people are spending that time reading a book that goes beyond what is written instead of reading what is written by God, the Bible. Our first reading should be in the word of God so we will not be fooled by fiction presented as truth. Heaven is for real, but I learned that reading the word of God validated by the resurrection of Jesus Christ (John 2:18-22).
Are you systematically learning the word of God. Make it a priority in your day every day.