When God created man, He created man in His image and likeness. Man, was to take after God's form and part of this was to have eternal life. However, when Adam and Eve sinned, they brought death and decay into the world. Even though man is now mortal, God has placed eternity in his heart because He wants us to be with Him forever. This longing for something more is a reminder that we are not meant for this world and that there is more to come.