http://en.wikipedia.org/wiki/John_3_16
John 3:16 is one of the most widely quoted verses from the Christian Bible. It has been called the "Bible in a nutshell", because it briefly summarizes the Christian faith.
The verse in the original Greek is as follows:
ουτως γαρ ηγαπησεν ο Θεος τον κοσμον, ωστε τον υιον τον μονογενη εδωκεν, ινα πας ο πιστευω&nu ει&sigmaf αυτον μη αποληται αλλ εχη ζωην αιωνιον.
Which could be translated literally as:
For in this way God loved the world: that he gave the unique Son, so that all those trusting in Him should not perish, but have eternal life.
The King James version renders it as:
For God so loved the world, that he gave his only begotten Son, that whosoever believeth in him should not perish, but have everlasting life.
For a comparison of different translations of this verse, see Bible translations.
The phrase "John 3:16" is very short and can be written in large letters on small signs. As a result, some Christians have intentionally displayed the phrase at sporting events (such as football games) so it might be televised.
The text of the verse is also incorporated into the Divine Liturgy of St. John Chrysostom, as part of a prayer said by the celebrant. This Divine Liturgy is commonly used in the Eastern Orthodox Church and in the Byzantine rite of the Roman Catholic Church.