Jesus wants us to remember that the words he speak are not just to be "incidental" in our lives, but a living part of who we are. If we really get the meaning of this passage, it can be life-transforming. Jesus tells us that we have to "work these words INTO our life" - not just roll them over a time or two, but really mull them over until they are ingrained into the fibers of our being! Having to "work" to get hold of what God has for us in the Word of God is sometimes more overwhelming than we would like, so we just don't do it. We hear them, but we don't really do much with them. The difference between "incidental" learning and "intentional" learning is significant. Incidental learning is that which happens without any coordinated effort on your part - it is almost accidental. Since there is no coordinated plan for learning, so when it occurs, it is called incidental. Incidental learning is almost always contingent on someone else's learning - in other words, we get the learning because someone else taught us what they had learned first. It is not wrong to get our learning this way, especially when the subject matter becomes a little easier for us to grasp when it is presented by someone who already has this stuff down pretty well themselves.
Intentional learning is the type of learning that is done with a purpose in mind. When you are intentional about learning, you know what it is you seek to learn about, then you use resources available to you to dig for the truths yourself, and you consult other types of references when you need to dig even deeper. With intentional learning, lessons are first-hand - they are 'work' for you, but the expenditure of effort yields a positive result. You come to know the truth yourself. This is the type of learning that Jesus was referring to here - "working the word" deep into your life so it impacts your every action - getting to know the truth for yourself. It isn't that we have to ferret out the truth - we allow the truth to become evident to us by becoming so familiar with it that we begin to realize how that truth can be applied in our lives.
Jesus refers to these intentional lessons as foundational - they give us a stability when times get tough. Rains come, strong winds blow, but we stand strong. How does that occur? Through intentionally allowing the Word of God to get worked into the very fibers of our being. At first, it seems hard and like nothing will ever make sense, but in time, little truths begin to pop off the pages at you. Most importantly, when you are working that word deep into your life, it is there when you need to stand upon it! That is why Jesus referred to it as "foundational". A foundation gives us stability when there is counter-pressure pushing against us that would seek to topple us. If you are like me, you want to get those walls and roof up quickly in your life (you want something to show for your efforts) - but you cannot neglect the grounding of a good foundation. A good foundation takes time to build. There is a footing that must be laid - it must be plumb and well positioned. If it is laid on sandy soil (a heart that really is not intent on holding to the truths), it will be difficult to build a solid foundation. As the footing of God's word is laid, then we are ready to "fill in the spaces between the footing" with the stuff that gives us the character to stand strong. Now, we have a foundation!
Maybe you are in the "footing" stage of growth - being made plumb and just beginning the work of having a solid foundation. Maybe your foundation has been laid for a while and it is time to begin to build upon it. Either way, God is eagerly awaiting the time you will take each day with him to allow him to assist you in "working" the word into your life - it is a mutual effort, intentionally performed, that yields the greatest results. The incidental learning will happen along the way, but we cannot rely upon this as the only means by which we grow up in Jesus. We need those moments of intentional, committed study to help us develop that solid foundation. Just sayin!