5 Eternity refers to the New Jerusalem that is coming after the Return of Messiah (Christ). Eternal Life refers to the access we NOW have, as God's children through Christ, to all that He has Promised in His Word.

Next the angel showed me the river of the water of life, sparkling like crystal, flowing from the throne of God and of the Lamb. Between the main street and the river was the Tree of Life producing twelve kinds of fruit, a different kind every month; and the leaves of the tree were for healing the nations — 3no longer will there be any curses. The throne of God and of the Lamb will be in the city, and his servants will worship him; 4they will see his face, and his name will be on their foreheads. 5Night will no longer exist, so they will need neither the light of a lamp nor the light of the sun, because Adonai, God, will shine upon them. And they will reign as kings forever and ever. Rev 22:1-5 CJB

Eye has not seen, ear has not heard, neither has entered the imagination of man... what God has prepared for us! 1Cor 2:9