Jude was a younger brother of Jesus and probably did not become a true believer until after the resurrection. He gained some prominence in the Jewish/Christian assembles and was moved by the Holy Spirit to write this epistle. In it he warns of false teachers and leaders who reject the Lordship of Christ. He warns against apostasy and the punishments to come.

Jude wrote to the Jews as he is Jewish.  This Jude in not the Apostle (there are two James’ listed as Apostles in Matt 10:2-4) but was the half brother of Jesus (Gal 1:19)(Mark 3:6) who became a leader (Acts 15:13) in the Jerusalem Church after the resurrection of Christ. He doesn’t quote directly the  scripture (OT) but he does reference parts of it in his very short Epistle.

Jude                                 King James Version (KJV)

1:6     And the angels which kept not their first estate, but left their own habitation, he hath reserved in everlasting chains under darkness unto the judgment of the great day.
This is not found in our OT writings. But in other writings not canonized. Or did he get it from the Holy Spirit?

1:7    Even as Sodom and Gomorrha, and the cities about them in like manner, giving themselves over to fornication, and going after strange flesh, are set forth for an example, suffering the vengeance of eternal fire. Genesis 13:10 And Lot lifted up his eyes, and beheld all the plain of Jordan, that it was well watered every where, before the Lord destroyed Sodom and Gomorrah, even as the garden of the Lord, like the land of Egypt, as thou comest unto Zoar.

Genesis 13:12 Abram dwelled in the land of Canaan, and Lot dwelled in the cities of the plain, and pitched his tent toward Sodom. Genesis 13:13 But the men of Sodom were wicked and sinners before the Lord exceedingly.

1:9     Yet Michael the archangel, when contending with the devil he disputed about the body of Moses, durst not bring against him a railing accusation, but said, The Lord rebuke thee.  This is not found in our OT writings. But in other writings not canonized. Or did he get it from the Holy Spirit?

1:11    Woe unto them! for they have gone in the way of Cain, and ran greedily after the error of Balaam for reward, and perished in the gainsaying of Core.          way of Cain Genesis 4:9    And the Lord said unto Cain, Where is Abel thy brother? And he said, I know not: Am I my brother’s keeper? 10 And he said, What hast thou done? the voice of thy brother’s blood crieth unto me from the ground.11 And now art thou cursed from the earth, which hath opened her mouth to receive thy brother’s blood from thy hand;12 When thou tillest the ground, it shall not henceforth yield unto thee her strength; a fugitive and a vagabond shalt thou be in the earth.

error of Balaam Numbers 22:10
And Balaam said unto God, Balak the son of Zippor, king of Moab, hath sent unto me, saying,11 Behold, there is a people come out of Egypt, which covereth the face of the earth: come now, curse me them; peradventure I shall be able to overcome them, and drive them out.12 And God said unto Balaam, Thou shalt not go with them; thou shalt not curse the people: for they are blessed.

gainsaying of Core Numbers 16:5   And he spake unto Korah and unto all his company, saying, Even to morrow the Lord will shew who are his, and who is holy; and will cause him to come near unto him: even him whom he hath chosen will he cause to come near unto him.

1:14  And Enoch also, the seventh from Adam, prophesied of these, saying, Behold, the Lord cometh with ten thousands of his saints, Genesis 5:22-24  And Enoch walked with God after he begat Methuselah three hundred years, and begat sons and daughters: And all the days of Enoch were three hundred sixty and five years: And Enoch walked with God: and he was not; for God took him.
This is not found in our OT writings. But in other writings, (not canonized) or did he get it
directly from the Holy Spirit?

1:15 To execute judgment upon all, and to convince all that are ungodly among them of all their ungodly deeds which they have ungodly committed, and of all their hard speeches which ungodly sinners have spoken against him. Psalm 149:7-9 To execute vengeance upon the heathen, and punishments upon the people;To bind their kings with chains, and their nobles with fetters of iron;To execute upon them the judgment written: this honour have all his saints. Praise ye the Lord.

1:17   But, beloved, remember ye the words which were spoken before of the apostles of our Lord Jesus Christ.      

JUDE was written as late as 75 AD, So was he referring to the Gospels, Epistles of Peter, James, and John?