What does John 3:16 mean?

This is the core of Christianity: that God loved the world enough to come as Jesus, and to die for us, so that anyone who trusts in Him will be saved from sin. This is certainly the most well-known verse in the Bible. It is probably the best-known and most-memorized part of any holy text in human history. The verse is a one-sentence summary of the gospel, and the subject line of the entire Bible. John 3:16 also reflects another important aspect of the gospel: the essential idea is extremely clear, but there are layers of meaning and knowledge inside of it.

The opening phrase is traditionally translated as "God so loved the world that…" and is typically understood to mean, "God loved the world so much that…" There is nothing incorrect about that idea, but the actual phrase means "God loved the world in this way," with emphasis on what God did, more than why. Jesus is an expression of God's indescribable love for "the world," meaning all of mankind (1 John 4:9–10).

The phrase translated as "One and Only Son," or "only begotten Son" uses the Greek word monogenes. This is a very precise word, and one which John uses in other places in this gospel (John 1:14; John 1:18; John 3:18). While the English term "begotten" often makes people think of biology, monogenes does not imply it. The word literally means something of the exact same "stuff." In other words, the Son is of exactly the same nature as God the Father. This makes John 3:16 an important part of proving the biblical concept of the Trinity.

The life offered to those who believe in Christ is "eternal," from a Greek word meaning "never ending." The alternative to life in Christ is destruction: to "perish." Verse 16 and 17 explain that the purpose of sending Jesus was our salvation, but verse 18 reminds us that those who don't believe are condemned. There is no question that, according to the Bible, people can be saved only through faith in Jesus.