“As I urged you when I was going to Macedonia, remain at Ephesus so that you may charge certain persons not to teach any different doctrine, nor to devote themselves to myths and endless genealogies, which promote speculations rather than the stewardship from God that is by faith.” (1 Timothy 1:3–4, ESV)
There are two categories of those who Paul condemns in these verses. The first is those to teach a different doctrine. The second are those who promote speculations (ESV) or controversies (NIV).
A different doctrine
In the first category I would put organizations like the LDS Church and the Watchtower Society. What sets them apart from Scripture is their teaching on the person of Jesus Christ and the means of salvation. They clearly teach a different doctrine than the catholic (universal) church has for the last two thousand years. When the teachings of these organizations are compared to Scripture, it becomes clear that their doctrine is different than what Scripture presents.
Those who promote speculation are often less obvious. We must be willing to look inside the Evangelical community with honesty to identify when we have begun to promote speculation.
For example, the Book of Revelation is full of symbols. It would have been so much easier if Jesus just gave us a timeline and provided specific dates and descriptions of events yet to happen. He did not. Therefore, we must look at the symbols to see what lessons are in them for us.
The danger in this is that depending on presuppositions we can come to different understandings of what the symbols mean. The fact that they are symbols that can be interpreted differently should lead us to caution in declaring that our understanding is the only right interpretation. Yet, there are many churches who make such a declaration.
Let us stand firm on the teaching in Scripture that is clear. About the meaning of the birth, ministry, death and resurrection of Jesus Christ we can be confident in our understanding. On those issues that are not clear or are open for interpretation, we mush allow for difference of opinion and be wary of those who promote only one possible understanding.
I am reminded of the phrase attributed to Rupertus Meldenius:
In essentials unity
In non-essentials liberty
And in all things charity