Most of it has to do with what manuscripts and Scripture portions the translation was translated from. The King James Version and the New King James Version are translated from manuscripts dating from A.D. 500-1000. Most new translations are produced using a combination of more recent discoveries of earlier manuscripts and fragments dating from A.D. 200-400. It is thought that since these manuscripts are older, they should be more accurate.

Most modern translations set off certain verses in brackets or move them into footnotes. This is because these verses are not found in some of the older manuscripts, and it is debated whether these verses were part of the original manuscripts or if they were added at a later time. It should be noted that the spiritual truths, concepts and information presented in these “debated” verses are not really what is under scrutiny, because this information can be found elsewhere in Scripture. The issue is whether or not these specific verses appeared in the original manuscripts. 

The New International Version and the New Living Translation often move debated verses into the footnotes. The New American Standard Bible and the Holman Christian Standard Bible leave the verses in place and set them off with brackets. The reasoning for the brackets is placed in footnotes.

All of the translations we have mentioned are considered to be among the many good and trustworthy translations available. We recommend studying from several good translations whenever possible.