Gospel

What is the Gospel?  As I grew up I considered the Gospel as the whole Bible. I thought that the Gospel was Jesus' teaching and such. 
            1 Corinthians 15. This verse says, "By this gospel you are saved, if you hold firmly to the word I preached to you. Otherwise, you have believed in vain. For what I received I passed on to you as of first importance: that Christ died for our sins according to the Scriptures, that he was buried, that he was raised on the third day according to the Scriptures, and that he appeared to Peter, and then to the Twelve. After that, he appeared to more than five hundred of the brothers at the same time, most of whom are still living, though some have fallen asleep. Then he appeared to James, then to all the apostles, and last of all he appeared to me also, as to one abnormally born." These verses help us understadn the gospel. Key points to this verse include the phrase "according to the Scriptures" ( If you dont have this on Mr. Seetoo's quiz you get points off). This phrase proves its validity, without it anybody could just say it and it would have no true meaning. Another important thing is that he appeared to all of these people. I could just say someone was raised from the dead but say no one saw it, this verse shows hundreds of people seeing Jesus after his resurrection. The Gospel isn't mainly focused on Jesus' teachings but rather the fact that he died for our sins, was buried, and rose again on the third day