A critic of the Church recently used Jude 1:3 as evidence against the LDS view of the Apostasy and the Restoration. Here is my response:
On Jude 3, that is not a verse that is opposed to the LDS view on the apostasy and a need for a Restoration.
Beloved, when I gave all diligence to write unto you of the common salvation, it was needful for me to write unto you, and exhort you that ye should earnestly contend for the faith which was once delivered unto the saints. (KJV)
The term translated as "once" is απαξ. It simply means "once" and does not, in and of itself, denote finality. Had Jude wished to convey such, he would have used εφαπαξ, which is used in the Greek NT for the once-for-all sacrifice and death of Christ (Rom 6:10; 1 Cor 15:6; Heb 7:27; 9:12; 10:10).
Notice how απαξ is used in the NT:
Thrice was I beaten with rods, once (απαξ) was I stoned, thrice I suffered shipwreck a night and day I have been in the deep. (2 Cor 11:25)
For even in Thessalonica ye sent once and again (απαξ) unto my necessity. (Phil 4:16)
Wherefore we would have come unto you, even I Paul, once and again (απαξ); but Satan hindered us. (1 Thess 2:18)
Whose voice then shook the earth: but now he hath promised, saying, Yet once more (απαξ) I shake not the earth only, but also the heaven. (Heb 12:26)
Two verses later in this text, Jude again used απαξ:
I will therefore put you in remembrance, though ye once (απαξ) knew this, how that the Lord having saved the people out of the land of Egypt, afterward destroyed them that believed not.
LDS scholar, John Tvedtnes, commented on this verse thusly:
If the gospel (more correctly, faith) was to be delivered but once to men on the earth, then Paul would be wrong in writing that the gospel had been revealed earlier to Abraham (Galatians 3:8f). And if the gospel was revealed in the days of Jesus, never to disappear from the earth, there would be no necessity for the angel John saw coming in later times to reveal the gospel to the inhabitants of the earth (Revelation 14:6-7). We can either conclude that Jude 1:3 does not give the whole story, or we must conclude that the Bible contradicts itself. That is, the same argument used against Joseph Smith can be used against the writers of the biblical books, if one misinterprets this passage. (source: http://www.jefflindsay.com/LDSFAQ/FQ_Restoration.shtml#jude)
The burden of evidence is based upon the person arguing their point that απαξ denotes once-for-all/sense of finality. Jude 1:3 is not evidence, however, against the LDS view on the nature of the Apostasy and/or a need for a Restoration.