God loved the world so that He gave
His only Son the lost to save,
That all who would in Him believe
Should everlasting life receive. 
God so loved the world. The Father sent His Son to be lifted up. By our very nature we are in grave danger. We aren’t plagued by snakes as the children of Israel were. But we are plagued by sin, which causes death. Christ came into the middle of our world, the snake pit, if you will. The Father lifted Jesus us on a cross, “and with His stripes we are healed.” (Isaiah 53:5) John 3:16 captures God’s plan. He loved us so much that He sent His Son to be lifted up for us.
Here we see that great exchange. Our sins and misdeeds are replaced by Christ’s righteousness. As your substitute, Jesus goes to the cross trading in your dead life for a new one, redeemed by Him.
This is how God loved the world. God's sacrificial and faithful love for the entire world alienated from God. God not only sent his Son but also offered Him to the world. He became our atoning sacrifice. By His sacrifice the world has been set free.
Finally, Note John's use of tense, "Should not perish," "has and continues to have life eternal," "Shall not die forever." Jesus is the end for what we hope not the means to that end.
Gracious Father, whose blessed Son Jesus Christ came down from heaven to be the true bread, which gives life to the world: Evermore give me this bread, that he may live in me, and I in him; who lives and reigns with You and the Holy Spirit, one God, now and forever. Amen 
1. Image: Jesus and Nicodemus, Schnorr von Carolsfeld woodcuts © WELS for personal and congregational use
2. God Love the world so that He gave, Lutheran Service Book © 2006 Concordia Publishing House, St. Louis
3. Collect for the Fourth Sunday in Lent, http://www.liturgies.net/Lent/LentenCollects.htm