Slide 41 of 49

All spiritual creatures (God Himself, angels, and humans) recognize that their spirits are eternal and will go through judgment of God, based upon their adherence to the laws of God. However, there are those who have told themselves long enough that there is no God that they have had this conscience or built-in "eternity in their hearts" dulled to the point that they no longer respond to it.

Additional Resource:

Eternity in their Hearts by Don Richardson

He has made everything beautiful in its time. He has also set eternity in the hearts of men; yet they cannot fathom what God has done from beginning to end (Ecclesiastes 3:11, italics added).

Don Richardson presents documented evidence from hundreds of primitive cultures from around the world that God, indeed, has put eternity into the hearts of men.