John 17:3
King James Version (KJV)
3 And this is life eternal, that they might know thee the only true God, and Jesus Christ, whom thou hast sent.
would certainly imply personal analitical testing, examination of one's denomination teachings, or history, or conduct
as it influences ones relationship to Jesus Christ
One of the striking things about new Christians is that they invariably begin to manifest a totally different attitude toward things they once thought were appropriate. In some of the more blatant forms of evil, such as attitudes about lying or drunkenness or stealing, they find immediately that their attitude is changed.
You may be asking, How can I know that? The answer is found in several places in Scripture. For instance, Scripture speaks of an inner witness. In Romans Paul says, The Spirit himself testifies with our spirit that we are God's children (Romans 8:16).
There had to be outer caution & testing too , involving others , within the congregation ,else scriptures like these would not appear..
For certain persons have crept in unnoticed, those who were long beforehand marked out for this condemnation, ungodly persons who turn the grace of our God into licentiousness and deny our only Master and Lord, Jesus Christ,~~~ jude 4