Why has he Risen? For Our Salvation!
Peter writing in the later years of his life (between A.D. 64 and 67) is supporting the teachings of Paul and speaks of Paul's letters as if they are on a level with other scriptures.
2 Peter 3:15 - And accounts that the long suffering of our Lord is salvation; even as our beloved brother Paul also according to the wisdom given unto him hath written unto you;
And what are some of the writings of Paul in regards to Salvation?
First he acknowledges that we are all sinners:
Romans 3: 10 & 23 - (10) As it is written, There is none righteous, no, not one: (23) for all have sinned, and come short of the glory of God;
Then we need to hear the truth:
Ephesians 1:13 - In whom ye also trusted, after that ye heard the word of truth, the gospel of salvation; in whom also after that ye believed, ye were sealed with that holy Spirit of promise,
What is the Gospel of Salvation?
1st Corinthians 15:1-4 - (1) Moreover, brethren, I declare unto you the gospel which I preached unto you, which also ye have received, and wherein ye stand; (2) by which also ye are saved, if ye keep in memory what I preached unto you, unless ye have believed in vain. (3) For I delivered unto you first of all that which I also received, how that Christ died for our sins according to the scriptures; (4) and that he was buried, and that he rose again the third day according to the scriptures;
What must we do? Believe the Gospel !!