There are days when I put a lot of time into playing guitar. I really want to get better at it, and the only way for me to get better and understand my instrument further is by practising it. Verses 6-10 of this chapter lean toward saying the same thing in regards to your faith.
If believers put as much effort into their spiritual life as they do in their recreation or hobbies, what a difference it would make! Physical exercise and development is important, but spiritual exercise is even more essential. As cheesy as this sounds, both discipline and devotion are needed to make a competent guitar player, a winning athlete, or an effective Christian.
Think about the things that are important to you. Your hobbies. Your family. Your work. You put countless hours of effort into those. But when eternity comes into play, what is actually the most important? Think about how much effort you put into discipline and devotion in regards to your spiritual life.