Enoch walked with God, and he was not, for God took him. (Genesis 5:24 ESV)
Enoch’s walk with God makes him an early example of faith, and his being taken by God without dying anticipates the eternal resurrection life that Christ gives.
Here is how the author of Hebrews puts it:
By faith Enoch was taken up so that he should not see death, and he was not found, because God had taken him. Now before he was taken he was commended as having pleased God. And without faith it is impossible to please him, for whoever would draw near to God must believe that he exists and that he rewards those who seek him. (Hebrews 11:5-6 ESV)
In addition to living a life of faith that pleased God, Enoch appears to have made a prophecy concerning the wickedness of the people in his own generation:
It was also about these that Enoch, the seventh from Adam, prophesied, saying, “Behold, the Lord comes with ten thousands of his holy ones, to execute judgment on all and to convict all the ungodly of all their deeds of ungodliness that they have committed in such an ungodly way, and of all the harsh things that ungodly sinners have spoken against him.” (Jude 1:14-15 ESV)
After Adam and Eve rebelled against God, sin entered the created order and humanity’s heart became wicked internally. The murder of Abel by Cain is the first recorded murder in Scripture. However even in the midst of such wicked and perverse generations, there was still hope that people like Enoch could live godly lives and escape the penalty of sin, which is death.
The faith that Enoch had was one where he rejoiced in God and denounced the evil ways of his peers especially as they progressively turned away from God.
Such a principle still holds true in our time just as it did in Enoch’s time.
Looking at Enoch’s example, it appears that faith can be understood as enjoying the person of God Himself, and sin is when we reject His person in pursuit of lesser pleasures.