In conclusion to Paul’s first letter addressed to his “true son in the faith” (1:1), he echoed once again his instruction for Timothy to safeguard the gospel message. This is perhaps the most important responsibility an evangelist has, as Paul so consistently noted (cf. 1:3, 18-20; 4:1-6, 16; 6:3-5, 12-14, 20, 21). Outer threats must be addressed and extinguished.
Among the threats to the faith are “the profane and idle babblings” which, among other things, would include “fables and endless genealogies” (1:4). These are things which have their origin traced back to the minds of men who, discontent with the gospel, revert to uninspired, thus empty and useless, writings and ideas. Something else mentioned by Paul was the “contradictions of what is falsely called knowledge.” This could include, but is not limited to, the aforementioned items of discussion. True knowledge is that which is inspired of God, i.e. that which “was committed to [Timothy’s] trust” – the gospel message.
The love some have for “false knowledge” is dangerous. When it strays concerning the truth, if continued to be followed, those “professing it” will stray. There are concepts from secular sources which may agree with even that which inspired scripture affirms. However, anything uninspired is severely dangerous. Those who place their faith in such do so to their own peril, for it is not from God, thus subject to error. An evangelist must refrain from reliance upon such sources, and trust solely in the word of God (cf. 2 Timothy 3:16-17).
Note: The KJV translates the latter part of verse 20 as, “oppositions of science falsely so called.” Sadly, even some brethren have failed to understand the order of thought concerning the universe. Modern technology and thinking does not trump God’s word. The faith God requires is to submit even to the inspired use of the word, “day,” in the creation account (cf. Genesis 1). Science that is true will harmonize with scripture. Not the other way around!