Everyone has a destination in life. Regardless of whether you are a new Christian or have been a Christian for years, you have a destination. Everyone who is a believer in Jesus has the same destination. We focus on Jesus.
If you focus on an object for long enough, you begin to drift towards the object. Have you ever noticed this? If you are driving down the road, and you start to stare at another car, you will slowly drift toward that car. The same applies in our walk with Jesus. Our focus is supposed to be on our destination. That is, worshipping Jesus forever, living out a personal relationship with Him. When we begin to focus on sinful things, we begin to drift toward them. Therefore, every Christian should follow the advice of the author of Hebrews. We should keep our eyes on Jesus.
The author of Hebrews also makes it clear in this passage that this Jesus, Who is to have our undivided attention, is both the author and perfecter of our faith. As the source of our faith, Jesus is where our faith begins. As the perfecter of our faith, Jesus is the One Who makes it perfect. He is the One Who grows it to full maturity. Because of this, our faith is to begin in Jesus, and remain in Jesus. Therefore, we should never allow ourselves to take the focus off of Jesus and onto sinful things. When we do, we will start drifting and end up crashing along the road to life.