Why Psalm 12:7 is not a 'preservation' verse for the Word...

As a start, we will look at the verse itself in the KJB -

 "Thou shalt keep them, O LORD, thou shalt preserve them from this generation                 for ever."

The KJB being based on the previous 'version' of 1568, called the Bishops Bible, which in its text says -
  
"[Wherefore] thou wilt keep the godly, O God: thou wilt preserve every one of                         them from this generation for ever." 

Evidently the KJB translators believed the 'them' in the (a) part of verse 7 to mean 'the godly', as per their note in the gloss of the original 1611 printing - which reads as follows -

   
"Heb., 'him', i. every one of them." 

Most "pro-KJB/KJV-only" Christians of the Baptist realm will refuse to believe such a thing, especially from one who does not follow their 'belief'.

In the 1537 Matthews Bible, there is a curious note in its gloss that might have started this whole thing. The note for the word 'them' reads as follows - 

 "That is, 'such and such men', after Kimhi. But after Abr. Ezra, 'thy words'."                 

Next we will see who Kimhi is, and who Abr. Ezra is.

Trim your lamps, brethren.