Charles Ellicott Commentary Psalms 36:2

"For he flattereth himself in his own eyes, That his iniquity will not be found out and be hated." — Psalms 36:2 (ASV)

For he flattereth ... —Literally, For he (or, it) makes smooth for himself in his own eyes to discover his iniquity, to hate. This is a very difficult sentence. We must look for the key to interpreting these words in the balance of the two phrases, “before his eyes” and “in his own eyes,” and we must consider the two verses together. In fact, they form an example of introverted parallelism. (See the General Introduction.)

Sin is the wicked man’s oracle in his heart;
No fear of God is before his eyes;
He makes everything smooth for himself in his own eyes.
As for the discovery of his guilt, that is his hate;

Or,

The discovery of his guilt is the only thing he hates.

This reading interprets the two infinitives as subject and complement, with the linking verb (copula) understood. It would be strange if Hebrew, which, more than any other language, uses the infinitive in various ways, offered no example of such a use. (For matsa aven in the sense of the discovery of guilt, compare Genesis 44:16; Hosea 12:8, and so on.)