But be ye doers of the word, and not hears only, deceiving yourselves."
James 1:21-22 (NKJV)
There are several sports that use a ball, such as tennis and golf. One thing that these sports have in common is that there needs to be a follow through of the swing made to hit the ball. If you would only hit the ball and then somehow stop your swing, then you are not hitting the ball correctly and you will not have the best and maximum result from what you are doing. Having a proper follow through is necessary to correctly hitting the ball the way that you need to.
In the same way that there needs to be a follow through when hitting a ball, as Christians, there needs to be a "follow through" of what we learn from God's Word, the Bible. In James 1:21, we see how we need to receive God's Word, and James 1:22 shows us the "follow through" of then doing what we learn from the Word. We need to receive God's Word, which then of course means we need to spend time with God's Word, in order to then become a doer of the Word.
If we are only hearing the Word and not doing the Word, we are deceiving ourselves and denying ourselves the positive benefits that come through the obedience of putting God's Word into practice in our life. It is one thing to hear God's Word, to memorize what we have heard, tell others about what we have heard, and even get excited about it; but that does not mean we are actually putting the Word into practice in our life. We need to hear God's Word, receive the Word, and do what the Word says.