Unbelief - Past, Present, Future

The cause of sin is unbelief.

The past
In the garden of Eden, Adam and Eve did not believe God that if they eat of the fruit of tree of the knowledge of good and evil, they will die.
And the Lord God commanded the man, "You are free to eat from any tree in the garden; but you must not eat from the tree of the knowledge of good and evil, for when you eat from it you will certainly die." (Genesis 2:16-17 NIV)

The present
Today, people see Israel becoming a nation but refused to believe that this is an act of God. God is putting Israel as His flag on earth, signally His intention to set up His kingdom soon.
In that day the Lord will extend his hand yet a second time to recover the remnant that remains of his people, from Assyria, from Egypt, from Pathros, from Cush, from Elam, from Shinar, from Hamath, and from the coastlands of the sea. He will raise a signal for the nations and will assemble the banished of Israel, and gather the dispersed of Judah from the four corners of the earth. (Isaiah 11:11-12 ESV)

The future
People are worried about climate change and the end of the world. They do not believe the Bible which said that the end of the world is still at least 1007 years away. There must first come 7 years of tribulation followed by the millennium rule by Jesus. Then only will the world end.
And he hath strengthened a covenant with many - one week, and in the midst of the week he causeth sacrifice and present to cease, and by the wing of abominations he is making desolate, even till the consummation, and that which is determined is poured on the desolate one.' (Daniel 9:27 YLT)
Then I saw thrones, and seated on them were those to whom the authority to judge was committed. Also I saw the souls of those who had been beheaded for the testimony of Jesus and for the word of God, and those who had not worshiped the beast or its image and had not received its mark on their foreheads or their hands. They came to life and reigned with Christ for a thousand years. The rest of the dead did not come to life until the thousand years were ended. This is the first resurrection. Blessed and holy is the one who shares in the first resurrection! Over such the second death has no power, but they will be priests of God and of Christ, and they will reign with him for a thousand years. (Revelation 20:4-6 ESV)