II Timothy 3:16-7a was written in the first century and in Greek. The Greek words written at that time can be translated
♦ “All Scripture is breathed out by God and profitable for |doctrine|, for reproof, for correction, for instruction which is in righteousness: that the man of God may be complete” (ESV|KJV, NKJV|ASV).
The Greek word translated “complete” is αρτιος and means “perfectly fit”* “entirely suited; complete”;** the relevant phrase in 3:17a can be translated to show regarding Scripture “It is God’s way of preparing us in every way” (NLT 1996).
*Friberg et al, Analytical Lexicon of the New Testament, page 76.
**In Perschbacher, The New Analytical Greek Lexicon, page 54.
From my perspective, the Lord was saying that the New Testament church's Scriptures were to be sufficient for a good Christian life. God “hath granted unto us all that things that pertain to life and godliness” (ASV) per 2 Peter 1:3, writen at around the same time. Hence, the New Testament church's Scriptures were to be sufficient for us.
That is why I believe that the Old Testament and Greek New Testament Scriptures should be the highest authority when it comes to Scripture. Hence, when any Reformation-era translation is at variance with archaeological evidence from surviving ancient manuscripts found after the Reformation, there needs to be a correction. During the Reformation period, different translations translated slightly different Greek texts; what the KJV translated in 1604-11 differed from what the 1607 Italian Diodati Bible translated, for example. Also, when studies of the ancient language and its meanings in the ancient world demonstrate that earlier translators' knowledge was incomplete, there needs to be some improvements.
I tend to accept a translation at face value unless it demonstrates being done by people who do not believe the Bible and are willing to let their views affect their rendering of the text. At Genesis 1:6, the NRSV and the NAB uses "dome," which would be consistent with the belief that Genesis 1 is another ancient creation myth. At 2 Timothy 3:16, the NJB does not translate the first purpose of Scripture of four found in the Greek; the NJB contains only the last three purposes. At 1 Corinthians 6:9, the REB and the 1970's edition of the RSV hide the injunction against homosexuality with a vague reference to sexual perversion.
The NAB -- not the NASB -- but the NAB is a Roman Catholic translation, and as such, had mandatory auxiliary material and notes that are considered part of the translation. In Genesis 11, a note about the account of the tower of Babel says "the secondary motive of the story is to present an imaginative origin of the diversity of the languages...as well as an artificial explanation of the name `Babylon.'" When I want to use a translation which Catholics would be most comfortable with, I use the old Douay-Rheims even though it is a translation of the Latin Vulgate translation.
In foreign language, I do not use the Spanish Biblia de Jerusalén because its auxiliary material places Daniel as a forgery written around 400 years after its time; for a Catholic Bible, I instead use the old Amat translation which is translated from the Latin Vulgate translation. I do not use the Portuguese Tradução Interconfessional because of similar statements in its auxiliary material.
I cannot express the `why' of my sentiment, but I am just uncomfortable with the notion of being told what the ancient Bible languages said by people who do not believe it for what it is.
There is one translation by Bible believers that I do not use. It is the NLT 2002. The translation of 2 Timothy 3:16-7 is changed, and does not give such hearty assertion to the sufficiency of Scripture. This comes one year after an NLT "Catholic Edition" which included the non-Scripture books that the Roman Catholic authorities inserted into the Old Testament. I believe the change, while possibly allowed by the ancient language, was more motivated by commercial concerns than by second-guessing of the translation's accuracy.
Otherwise, I tend to consider as worthy of consideration any translation done by Christians who believe the Bible to be what it is. I usually trust the simplicity of their `motives' as simply wanting to convey best the communications of the original languages.
Each translation type has its uses. For greater precision, formal equivalence, which is word by word, is most often best -- unless what is communicated by those words would be lost. However, to communicate with children or those for whom simpler vocabulary and sentence structure is best, dynamic equivalence, which goes statement-by statement, is the best way to go -- in my opinion. As one should be able to see from my present footer, I use both types.