1 Peter 1:12

"It was revealed to them that they were not serving themselves but you, when they spoke of the things that have now been told you by those who have preached the gospel to you by the Holy Spirit sent from heaven. Even angels long to look into these things." NIV translation

The prophets of the Old testament told of the coming of Jesus Christ and they knew that it was for a time in the future. They were serving us in helping us to understand more about God and His plan.

1 Peter 1:13

"Therefore, prepare your minds for action; be self-controlled; set your hope fully on the grace to be given you when Jesus Christ is revealed." NIV translation

When you see "therefore" in any part of the Bible, it is always good to go back and review what you have just read. In this case, it is telling us that, because of the salvation that we have, we are to be prepared to act differently. Peter says we are to be "self-controlled" which we are told, (in Galatians 5 by Paul), is a fruit of the Spirit. That tells us that it is from God and that we cannot do it on our own but through the Spirit we can overcome. Peter also reminds us to focus ("set your hope") on the gift of a new life in Christ that we have today (where we can be self-controlled) and a new life when Jesus returns (a life for eternity with Him). We must always remember that it is a gift (that's what grace is).