When we hear the word "gospel", our minds immediately turn to the four books at the head of the New Testament. Originally, though, this word had a more expansive meaning.
The word 'gospel' literally means, "good news." It was first used by a different kind of king than Jesus: the Roman emperors. They used this word at the head of any proclamation or message to the people, regardless of the content of the message. Using this word reinforced the cult that the emperor was a god bringing about the salvation of the world through his rule. A message beginning with "gospel" was just the latest example of how they were bringing salvation.
By Jesus using this word, He sets Himself up in opposition to Caesar. Instead of a man claiming to be a god, here is God's own Son. Caesar's words and the actions of his military imposed his will on a people. Jesus' freely offers His message of turning away from sin and freely accepting the will of the Father by which one receives a fruitful life. Caesar can't guarantee abundant life. Jesus does through His Passion and Resurrection. (See Pope Emeritus Benedict XVI's "Jesus of Nazareth," vol. 1, pages 46-47.)
The Gospel, then, to which Jesus refers is Himself. God has come to be with His people and lead them out of slavery to sin to the freedom of life with God.
Our question also refers to other gospels being the Gnostic Gospels. These have names based on people who lived at the time of Jesus, but these gospels do not have roots in these individuals. They were written hundreds of years after Jesus' time. While some of the stories are similar to those in the Bible, they have a different purpose.
Gnosticism believed that receiving the message of Jesus and being baptized wasn't enough to be saved. One must also have secret knowledge, a password, if you will, that you would be asked when you reached the time of judgment. The Gnostic Gospels were written so that, as one rose through the Gnostic cult, one would gain greater insight into the knowledge hidden within the words of the gospel and thus know what one needed to know to get into heaven.
The Catholic Church has firmly stood againstthis for centuries. From the times of the apostles, she has taught one needs to accept the message of Jesus, live according to that message and receive the sacraments in order to be saved. Guiding her in this truth are the four Gospels in the New Testament. All of these were composed by the year 100 A.D., meaning we have the writings in our Bible that are the closest to the time of Jesus. These give us the clearest understanding of Jesus and His message of salvation for us all.
Father Mayo is pastor of Holy Rosary Parish in Warrenton.