When it comes to the Word of Truth, the pure Gospel itself ... mixture with anything else becomes a deadly and lethal thing!
Just a little poison mixed into the most healthy meal or drink can kill you and totally defeats the good qualities and nutrients of that meal.
A little leaven, hey?
You don't need much to contaminate all of it. 1 Co 5:6&9
Present-day Babylonian teaching is exactly what it is. The word Babylon means confusion by mixture. It originated from the Hebrew word bâlal or בּלל that means to mix, mingle, confuse or fade a matter.
The ancient word-picture conveys the message very accurately. The בּלל word-picture is the house control controlled. Wow!
The control you have as the ekklēsia yourself (see here) is being controlled by something (or someone else), instead of you having dominion. Remember the very first instruction given by God onto man in the Garden of Eden? Thus, the pictograph of the word Babylon points to some foreign control depraving the control man was created and purposed to exercise.
Let's move along
What does the Apostle Peter say about this?
As newborn babes, desire the sincere milk of the word, that ye may grow thereby: If so be ye have tasted that the Lord is gracious. 1Pe 2:2-3
Peter was writing an epistle to people scattered throughout the middle-east and Asia, encouraging that they are the elect of God and saying that the resurrection of Jesus Christ gives them a lively hope, an inheritance which is incorruptible and undefiled and does not fade and is absolutely reserved. Go read it yourself!
Peter reassures them by saying that they have been made holy and were purified and that they should not give ear to anything or anyone that says anything different - to desire the sincere milk.
What is sincere milk?
In the Greek the word Milk points to pure Truth (Jesus). The word sincere or adolos is a compound word comprising of the prefix a, meaning without or privation of - it is much like the word asymmetric that means without symmetry. The prefix a is compounded with the word dolos that means deceit or guile. Thus adolos - without deceit.
It's really to be or not to be ...
So, adolos would be undeceitful, that is unadulterated, unmixed, incorruptible.
Let me paraphrase.
Peter is saying as new born babies (those who hear and receive the Gospel of Grace in its purest form, those who tasted the intimacy of His goodness and graciousness), we must desire and aspire to hear and receive the pure, unadulterated Truth only.
Wait! Didn't Jesus talk about this?
Jesus says in Matthew 18:3 that unless we become like little children, we will not see the kingdom of God. He says not to hinder the little children to come to Him.
How then does a little child come to Jesus?
Unpretentious.
With zero consciousness of the law and having 100% full persuasion of the graciousness and kindness and love and goodness of the Person of Jesus.
A little child takes no regard of the consequences of any law that might hinder him or her to proceed into the arms of Jesus. There is absolutely no mixture of any rules or prescripts or ordinances with the love they came to taste and experience.
Unpretentious.
Unfazed!
... if He says come, what is there to reason about?