Enoch lived sixty-five years, and became the father of Methuselah. Then Enoch walked with God three hundred years after he became the father of Methuselah, and he had other sons and daughters. So all the days of Enoch were three hundred and sixty-five years. Enoch walked with God; and he was not, for God took him. [Genesis 5:21-24]
The first reference to Enoch is recorded in Genesis. Unknown to many of us, Enoch actually prophesied and his prophecy is recorded in the Bible.
It was also about these men that Enoch, in the seventh generation from Adam, prophesied, saying, “Behold, the Lord came with many thousands of His holy ones, to execute judgment upon all, and to convict all the ungodly of all their ungodly deeds which they have done in an ungodly way, and of all the harsh things which ungodly sinners have spoken against Him.” [Jude 14 -15]
The apostle Jude wrote the above. I do not know where he got his source or reference as this quote is not recorded in Genesis. Most probably Jude was inspired by the Holy Spirit. In that case the message by Enoch is the oldest prophecy recorded in the Bible.