It is almost certain that the first "of" should be taken as objective (i.e. "the good news about Jesus", not "the good news from Jesus", which would be subjective). I will take the point for granted here- challenge me in the meta if you disagree.
This means at least two things:
- Mark's book is about Jesus.
- Mark's book is not about you.
At a basic level, that is a good question. I encourage it and I practice it myself. But that is often an easier question to answer when we read the Epistles than when we read the Gospels. The command to always be edifying in Ephesians 4 directly challenges what comes out of our mouths. "How do I apply this to my life?" is a simple question: I need to always be edifying!
But then we read the stories of healing in the Gospels and think, "OK, so Jesus can heal. That's nice. I'll pray for healing." Then we get bored when the Evangelist piles up a few stories in a row on the subject. We can think of no other application, so we skim until we get to some of Jesus' teaching, since that is easier to know how to apply.
All of this is why we need to remember that the Gospels, as Mark makes clear, are not about us. The application question can mislead us to always be looking for ourselves in the text.
But the Gospels aren't about us.
The Gospels are about Jesus.
So as you work through the Gospels, ask "What does this text teach me about Jesus?" The practical benefits will almost always fall into place when we do this, because quite simply, when we get Jesus right, we'll get our lives right.
For all of its good, the application question can also be symptomatic of the cultural value on the self. Focus on Jesus, brothers and sisters! Mark tells you that Jesus is his subject. He should be yours too. Fix your eyes on our Lord, and be amazed at how easy the application comes along.