God revealed things in truth. But human responsibility should not be denied. Believers among them should preserve the revelation from God the best they can, this includes copiers, and now translators and publishers. Being that all to whom revelation from God is provided are still human, and errors come up from time to time, in different places where copies were made. Mostly it would be equivalent to spelling differences. We do not have any of the autographa, so we can't say there is a manuscript without any error, and other copies are rightly considered to figure out what was said originally. And it is known that some things were changed, with a very few cases of additions or things left out. We still know enough from revelation from God that we have even with that the way to have right beliefs and with being in Christ to live right and still grow in godliness.