God is Love and whoever remains in Love remains in God, and God in him. –1 John 4:16
In perfect Love there is no fear, rather perfect Love casts out all fear. –1 John 4:18The Feast of St. John the Evangelist—the Apostle, the Beloved Disciple—is no doubt a great feast day of God's Love. St. John was the first to use Love as the perfect synonym for God, and as the last apostle to die as well as the author of the last book of the Bible, John is in many ways the last word on Love (with a capital "L") as well. So while the divine answer to the question, "Who wrote the book on Love?" will always be the Holy Spirit, the human answer has to be the Beloved Disciple.
But to understand who St. John is, one has to realize who he is not. St. John is not St. Matthew. Matthew's gospel is the proof of the mathematician. John's is the pondering of a poet. Matthew's gospel is everyday faith. John's is otherworldly Love. Without Matthew, the Faith wouldn't be grounded. Without John, the Word would not soar like an eagle, the valiant bird that also happens to be John's symbol.
John is also not Peter. Although John's steadfastness seemed to have earned him a spot closer to Christ's heart than the others, it was the impetuous Peter who was chosen to head Jesus' Church on earth. Mystics do not make great statesmen and poets do not make great popes. But before you start believing that effeminate DaVinci Code crap, the younger "Son of Thunder" was just as much a man as "The Rock." For while Peter followed Christ in being crucified (upside-down, no less!) for the faith, John was the only man who Loved our Lord enough (and had enough guts) to be present at His Crucifixion. The Church (and the priesthood) need them both.
But of all the wisdom contained in John's gospel, three epistles, and the book of Revelation, John's "Love" is summed up in the two above quoted verses. The first reminds us that if you don't Love everything God gives us, the riches and poverty, the beautiful and the deformed, the joy and the sorrow, we don't yet know (or LOVE) God. The second is similar; if we are still afraid of anything whether of what people will say, or what sacrifice will cost, or what tomorrow will bring, we still cannot really Love Christ. I am far from being all accepting or totally fearless myself, but having glimpsed John's vision, I can tell you there is nothing on earth that even comes close.
So do not be afraid that you do not yet see God's Love as John did, for "In the world you will have trouble" (John 15:33). For I am hear to say that, combined with the Sacraments, John's words are sure to shed enough Son Light on the subject to start you on the Way to the Truth and the Life (John 14:6).