In Jude 1:5 of the English Standard Version (ESV), we read that Jesus delivered the Israelites out of Egypt:

Now I want to remind you, although you once fully knew it, that Jesus, who saved a people out of the land of Egypt, afterward destroyed those who did not believe.

Other translations, including the KJV, NASB and NIV, instead read ‘Lord’ in place of ‘Jesus’ here.

Why the discrepancy?

This is not just a random decision to replace ‘Jesus’ with ‘Lord’, or vice versa. The translators are looking at the manuscript evidence and deciding what they believe the original reading most likely is. The critical editions of the Greek New Testament that many modern translations rely heavily on, the Nestle-Aland 26th and 27th editions, read ‘Lord’ in this verse. It was only in the recently released edition, the 28th edition, that the reading ‘Jesus’ was preferred.

The decisions of which readings to prefer in the critical editions are not made by one person, but rather by a committee of scholars. Dr. Bruce Metzger was one of several scholars who participated in the committee that chose ‘Lord’, and in his textual commentary he communicates the exact reason why it was preferred:

Despite the weighty attestation supporting Ἰησοῦς (A B 33 81 322 323 424c 665 1241 1739 1881 2298 2344 vg cop, bo eth Origen Cyril Jerome Bede; ὁ Ἰησοῦς 88 915), a majority of the Committee was of the opinion that the reading was difficult to the point of impossibility, and explained its origin in terms of transcriptional oversight (ΚΧ being taken for ΙΧ). It was also observed that nowhere else does the author employ Ἰησοῦς alone, but always Ἰησοῦς Χριστός. The unique collocation θεὸς Χριστός read by P72 (did the scribe intend to write θεοῦ χριστός, “God’s anointed one”?) is probably a scribal blunder; otherwise one would expect that Χριστός would be represented also in other witnesses. The great majority of witnesses read ὁ before κύριος, but on the strength of its absence from א Ψ and the tendency of scribes to add the article, it was thought best to enclose ὁ within square brackets. (Metzger 723)

After explaining the Committee’s rationale to prefer ‘Lord’ over ‘Jesus’, Metzger then follows with his own dissenting opinion:

[Critical principles seem to require the adoption of Ἰησοῦς, which admittedly is the best attested reading among Greek and versional witnesses (see above). Struck by the strange and unparalleled mention of Jesus in a statement about the redemption out of Egypt (yet compare Paul’s reference to Χριστός in 1 Cor 10:4), copyists would have substituted (ὁ) κύριος or ὁ θεός. (Metzger 724)

In Bruce Metzger’s dissent, he states that ‘Jesus’ is “the best attested reading among Greek and versional witnesses” and that “critical principles seem to require the adoption of Ἰησοῦς [Jesus].” In other words, a theologically unbiased decision based purely on the principles of textual criticism would prefer ‘Jesus’ here—not ‘Lord’.

The reason for it not being chosen was that a majority of the Committee felt “the reading was difficult to the point of impossibility.” They were convinced, it seems, of the extreme unlikelihood that Jude would have written that Jesus was alive and active within an Old Testament narrative. Perhaps they couldn’t stomach the idea that the earliest Christians believed Jesus existed prior to His physical human birth, something scripture itself attests to in John 1:1.

Fortunately, the reading ‘Jesus’ is now chosen in the Nestle’s critical text, even though Dr. Metzger is unfortunately no longer with us.

Metzger, Bruce M. A Textual Commentary on the Greek New Testament; a Companion Volume to the United Bible Societies’ Greek New Testament (2nd Ed.). N.p.: Hendrickson Pub, 2006. Print.