An oracle is within my heart
concerning the sinfulness of the wicked: 
There is no fear of God
before his eyes.
For in his own eyes he flatters himself
too much to detect or hate his sin.
The words of his mouth are wicked and deceitful;
he has ceased to be wise and to do good.

The Psalmist is teaching that sin is more than an action. He teaches that "sin within the heart of man".This is a figure of speech in which  the part is meant for the whole. Its not just his heart but it is the whole being. He is teaching that since sin is in the man from head to toe that man is totally depraved. Even if we were able to change our behavior yet sin will not be removed from our thoughts and the words we use. The sin of the thoughts and tongue are judged by the standard of the discipline of thinking the law, covenants, curses, statutes, promises and decrees -THE ORACLE. Even if the man was saved this standard of thought and action show that God must forgive sins by grace or even the believer would not measure up. THE TRUTH!!"An oracle is within my heart" The Psalmist uses extreme words when describing the sin that affects the wicked. He says there is no fear of God in the wicked. The extreme description is to show that the wicked are not just under the judgement of God but the Psalmist is describing the terrible condition to show the danger of the wicked so that it is necessary to curse them.

He is teaching that sin is rebellion toward God. This term is also used for the sin committed by christians. But think about this. If the christian is not thinking according to the axioms, just out of a lack of knowledge their thoughts are rebellious.You see the standard of Gods judgement in what we understand is extreme. Even if we pronounced the axioms every minute of the day we still would not be acceptable  to God. And if we pronounced them with great discipline think about all the believers who had no knowledge gained from the law, covenants etc. They would be condemned for a lack of care of Gods sayings! Oh how man are self deceived in  their own religious fervor!

The Psalmist is speaking the axioms in order to develop the attitude of fear that God requires about the sinner. Just think about all  the chritians who fail to develop this fear. They refuse to hate sin in the curse! Think about how much grace is required by God! Think about the low times in church history. All of the laziness and the lack of understanding. We would all be nigh unto cursing. THE PSALMIST IS JUDGING BY  THE ORACLE.. THE AXIOMS PEOPLE!