Chapters 5 to 6:8 form a section of Genesis giving the generations of Adam (Genesis 5:1 ), linking Adam with Noah.
The earlier account of man's creation is summarised here (Genesis 5:1,2 ). Male and female are
included in the name Adam, or as the New King James translates, 'mankind'. God's true view of fallen
mankind is revealed in this period of man's history - the prophetic commentary of Jeremiah 17:9 needs to
be accepted.
Of all mankind, he and Elijah (2 Kings 2:11 ) have alone escaped physical death. Their translation demonstrated that victory over death is included in redemption. Further, their translation prefigured the rapture and translation of all living saints at the second coming of our Lord Jesus Christ. "... in the twinkling of an eye ..." (1 Corinthians 15:51,52; 1 Thessalonians 4:17. ) We shall not all die before Jesus returns. Living saints bodies will know instant change from 'mortal' bodies to 'immortal' bodies. (1 Corinthians 15:53,54 ). Enoch represents the church's witness during the evil last days - its triumphant walk/life - with the Lord forever.
The name that was prophecy was fulfilled - the flood came when Methuselah was gone. Lamech - not the
wicked one of Genesis 4:23, God's man, called his son Noah, meaning 'comfort'. He was trusting in the
promise of Genesis 3:15. Judgment was coming, as Enoch had prophesied. Noah was God's comfort and
mankind's in that he was to be preserved and the preserver of man.
3.1. A SUMMARISED ACCOUNT OF CREATION (Genesis 5:1,2)
Jeremiah
17:9"The heart is deceitful above all things, And desperately wicked; Who can know
it?"
3.2. A SIGNIFICANT GENEALOGICAL TABLE (Genesis 5:3 to 32)
A comment by Ryrie is helpful: "Each reference to a patriarch gives
four details: (1) In his name. (2) His age at the birth of his first son. (3) The length of his
remaining life, and (4) the age at death. There are variations in the cases of Adam (verse 5)
Enoch (verses 22-24), and Lamech (verses 28,29). The longevity of the patriarchs (average
age 912 years, not including Enoch who did not die), may have been due to the canopy (1:7),
the waters which were under the firmament. Apparently God suspended a vast body of water
in vapour form over the earth, forming a canopy that caused conditions on earth to resemble
those inside a greenhouse, which was not dispersed until the flood."
A further reason for longevity could be simply the fact that it took some time for the effects of sin to shorten
man's life span.
3.3. A STARTLING EXCEPTION - ENOCH (Genesis 5:21-24)

Enoch is an exception in this chapter, to the dismal refrain 'and he died.' 
Enoch was right with God (Genesis 5:22 ). He lived right with God amidst an evil generation. He lived right with God fulfilling all family obligations. 
Enoch was pleasing to God.
Hebrews 11:5
"He had this testimony, that he pleased God."

Enoch had faith in God. By faith lived - by faith translated.
Hebrews 11:6
"But without faith it is impossible to please Him."

Enoch walked harmoniously with God (Genesis 5:22 ). In step with God - in desire - direction - determination.

Enoch spoke prophetically from God. (Jude 14 ). He named his son Methuselah prophetically (Genesis 5:21 ). The name means 'when he is gone it will come.' An announcement of judgment - he lived 969 years, revealing God as slow to anger and abundant in mercy and truth. 
Enoch was a bold prophet - fearless in his witness - he denounced the prevalent wickedness. He foretold the second coming of Christ in judgment (Jude 14,15 ). 
Enoch was translated by God (Genesis 5:24 ).
Hebrews 11:5
"By faith Enoch was taken away so that he did not see death, 'and was not found,
because God had taken him'; for before he was taken he had this testimony, that he
pleased God."
3.4. A SURE WORD OF PROPHECY (Genesis 5:25-27)
Genesis 5:27
"So all the days of Methuselah were NINE HUNDRED AND SIXTY-NINE YEARS."