Verse 28, explains that God turns His back on you, closes His eyes and ears to you, and otherwise ignores you. And verses 29 and 30, explain why.
When God is not watching over you, or otherwise not paying attention to you, it is not because of a defect in God, but is always a result of you, your actions, your thoughts, and your attitude.
There are two kinds of knowledge.
The first kind of knowledge, is that which we are all used to, and know about from our everyday life. We generally call this academic or experiential knowledge. It is what we learn in school, or from our day-to-day life.
The second kind of knowledge, comes to us by means of our day by day Bible study. Bible study, when done in the correct way, opens our eyes and understanding to the realities of life, and orients us to the realities of life and of this world. Bible doctrine gives us the correct interpretation of facts and how they relate to reality.
The first kind of knowledge is simply world knowledge. This gives us information, but does not give us the correct interpretation of that information. Consequently, misinterpretation can and does occur. Misinterpretation leads to false conclusions. False conclusions lead to wrong decisions. And wrong decisions lead to failure and disaster.
For example, evolution comes from the observation of worldly things. Evolution rejects the role of God in creation. Evolution is world knowledge which has been misinterpreted, leading to wrong conclusions.
Another example, when you look at world governments like socialism, or communism, or dictatorships, and so forth, then world observation is misinterpreted as conclusions are guided by the sin nature, such as in power lust, or convenient views of equality, and so forth. And such things in reality, do not exist. They are illusions which cater to selfish interests.
And the biggest example is when people ignore Bible doctrine, and presume that they already know enough, or do not need a daily study in Bible doctrine. And this is the biggest mistake of all.
The reality is God, and truth, which comes from Bible doctrine.
To ignore God and truth, in the worst case scenario, means the Lake of Fire. Under another scenario, for believers in Christ, who ignore their daily study, then lack of Bible doctrine, means lack of knowledge, means imitating unbelievers, and otherwise making the typical mistakes that the common man without doctrine makes everyday.
Therefore, by rejecting doctrine, you are rejecting truth. And by rejecting truth, you are rejecting God and all that He stands for and is.
Consequently, since God operates on truth, then by rejecting truth, you are in effect shutting God off from yourself.
Study [by instruction],
to show thyself approved [spiritually mature]
a workman [student]
that need not be ashamed [ignorant],
rightly dividing [learning, understanding, discerning]
the word of truth [Bible doctrine].
If you can dream and not make dreams your master,
If you can think and not let thoughts narrow your views,
If you can meet triumph with disaster equally,
If you can learn and see your full meaning and purpose in life,
Then you can believe in Christ, learn Bible doctrine, and grow far beyond the potential that God has prepared for you.