"The heart is deceitful above all things, and desperately wicked: who can know it?" (Jer 17:9).
The heart is very deceitful, it is good at deceiving its own self. You think you are doing something right and good but all the while you are all about your selfish agenda. It is all about you, you are not expressing Christ, you only care about yourself. These are the things that the spiritual man considers, he does not get overwhelmed with all the things happening physically, with all the appearances appeasing his carnal senses. He is most concern with what is in the heart; how to manifest Christ, how to get Christ into the heart, how to get the heart filled with Christ, because "out of the fullness of the heart does the mouth speak" (Matt 12:34). And because he gives more attention to the heart, he is able to notice the deception in it.
The more you focus your gaze on something the more you are able to see things and notice things that others didn't notice. You are so concerned about outward things and you get so overwhelmed with it that you didn't notice your heart deceiving itself, you didn't notice ignoring the truth and pushing it away till you accept a lie. Everything happened so subtle and so fast that you didn't notice, you are so overwhelmed with outward appearance that you didn't see all those things playing out inwardly. Yes, every one of us is guilty of this; we think what God desire is all these outward things, and we are so focused on them that we didn't notice the subtle hypocrisy going on in our hearts. The heart is so deceptive that it keeps tricking you, making you feel you are doing the right thing, but you are nothing but a hypocrite.
We all need to run to God, ask for mercy and repent. But even in this repenting, we are often deceived in our hearts. We repent and then find ourselves going back to the same thing. You begin to wonder, "why do I keep going back to this thing, but I repented". No, you haven't truly repented, you think you have repented but you didn't, your heart has deceived you again, because you have not been listening closely to the heart. Yes, it requires a lot of attention to catch the heart red-handed. If you do not pay attention to the heart you would keep going in circles thinking you have truly repented. You will put the blame on so many things and keep missing it.
Oh, the heart is so deceptive, who can know it? Only those who would stop getting so overwhelmed with outward appearances and start paying close attention to the heart. It is only a spiritual man that can truly please God. While the carnal man is all about appearances, the spiritual man is tending to his heart, for God looks at the heart. Oh, can we have people who knows how to tend to the heart like a garden, allowing Life (Christ) to grow in the riches of his, just as flowers filling the whole garden? When our hearts have become so beautiful and so rich with Christ then it becomes easier to manifest him more purely. If your heart is not pure your manifestation of him cannot be pour. The heart is so essential, tend to it.