Before I graduated from high school I had taken five years of Spanish, starting in 8th grade and then every year through my senior year. Toward the end of my senior year, I was in the Spanish club and one day I stopped in the class to grab something . It was after school and I was the only student in the room. My teacher, Señor Nisttahauz, stopped me and began to chew me out. He began to jump all over me because, as far as he was concerned I was lazy. In his eyes, I understood the language, knew the syntax and the grammar, had a firm grasp of the vocabulary, but I was lost in a conversation. Señor Nisttahauz believed that, with everything I knew, I should be fluent and the only reason I wasn't was because I never practiced speaking Spanish outside the classroom. I knew enough to pass my tests (ace my tests) but he was convinced that if I didn't start practicing, I would be one of those parents who showed up at an open house with their own child saying, "Yeah, I took Spanish in high school and I don't remember a word of it." He rightfully berated me for my laziness and I soon began practicing and my Spanish fluency improved greatly.
In many ways, the Christian walk is like learning a new language. Learning the appropriate words and actions is one thing, actually practicing and understanding them is something else entirely. The author of Hebrews expressed frustration over this particular problem, saying, "We have a great deal to say about this, and it's difficult to explain, since you have become lazy to understand . Although by this time you ought to be teachers, you need someone to teach you the basic principles of God's revelation again. You need milk, not solid food. Now everyone who lives on milk is inexperienced with the message about righteousness…" (Hebrews 5:11-13, HCSB). Essentially, the author argues, "You've been at the Christian life for too long to be at the level you are. You are inexperienced and lazy so you can't handle the tougher things that a person in your position should."
Because of the sin that lives in us and the fact that our natures have been corrupted, many of the teachings of the Word of God run against the grain of our natures and are difficult, if not impossible, to understand until we begin practicing them. We may "know" the teachings in much the same way that I "knew" Spanish in high school, but until we start practicing it, until we start using what we know, we will never really understand the Word of God, and we will never mature as believers. Jesus told his listeners that the way to know whether his teachings were really from God or not was to make a decision to do the will of God and not simply know it (John 7:17).
Has your understanding of the Word of God stalled in its growth? Have you come to a place where you don't understand as much as you think you should, where things don't make sense like you want them to? Maybe, you need to try putting what you know into practice, not just being satisfied with possessing morsels of knowledge. You'll never be fluent until you start practicing.