The book of Jude contains many quotes and references to the Old Testament. However, there are two quotes which seem to be from elsewhere.
The first is attributed to The Assumption of Moses.
Jude 9 But even when Michael the archangel was arguing with the devil and debating with him concerning Moses’ body, he did not dare to bring a slanderous judgment, but said, “May the Lord rebuke you!” [NET Bible]
However, no surviving copy of Assumption contains this quote. Origen is the first on record to attribute it this way. Some say it is an allusion to Zechariah 3:1,2.
The second is a direct quote from 1 Enoch 1:9.
1:14-15 Now Enoch, the seventh in descent beginning with Adam, even prophesied of them, saying, “Look! The Lord is coming with thousands and thousands of his holy ones, to execute judgment on all, and to convict every person of all their thoroughly ungodly deeds that they have committed, and of all the harsh words that ungodly sinners have spoken against him.” [NET Bible]
Did the author of Jude consider these works to be authentic Scripture in the same vein as the Tanakh? Do these quotations demonstrate the early Christians and their Jewish contemporaries had established a larger canon that was later reduced? In short, why did Jude quote from these materials?