But the way of the wicked shall perish [closed]
Solution 1:
I think that your instinct is correct and so do two Hebrew scholars. Conceptually, 'for' leads to a decisive conclusion ; 'but' diverts to another concept - which creates somewhat of a hiatus in the mind.
Young's Literal Bible (1862) - a very literal rendering of the original Hebrew - translates the verse as follows :
For Jehovah is knowing the way of the righteous and the way of the wicked is lost.
Green's Literal (1993) is almost exactly the same :
For Jehovah is knowing the way of the righteous and the way of the wicked shall perish.
Textus Receptus Bibles - Psalm 1:6
These two Hebrew scholars are translating the 'conjunctive waw' as 'and' rather than 'but'.
Biblehub Psalm 1:6
My own understanding of the wording is that Jehovah, the Lord, observes, knows, is aware of - and also directs, chastens and guides - the way of the righteous.
As is also stated in another Psalm :
Though the Lord be high yet he hath respect unto the lowly : but the proud he knoweth afar off.
Textus Receptus Bibles - Psalm 138:6
He holds such persons at a distance, knows them from afar, has little to do with them. They go their own way. And their way is self-destructive.
Note on Terminology
'Righteous' in the bible means 'justified', which is a matter of faith.
Abraham believed God, and there was evaluated to him - unto righteousness.
[As stated in Genesis 15:6 and Romans 4:3 and Galatians 3:6.]
Solution 2:
Hebrew poetry makes up one-third of the Old Testament.
At the "Introduction to Hebrew Poetry" page, the author describes the general characteristics:
A. It is very compact.
B. It tries to express truth, feelings or experiences in imagery.
C. It is primarily written not oral. It is highly structured. This structure is expressed in:
balanced lines (parallelism)
word plays
sound plays
In particular, let's draw our attention to C1 (parallelism). When the Psalms were translated into English (and most other language as well), most translators preserved the notion of poetry by arranging the phrases using indented lines. The King James Version translators sometimes used conjunctions to heighten the parallelism.
Here is a graphic that describes a chiasm in Psalm 1:6. Parallelism in Hebrew Poetry
To directly answer your question, the "but" in Psalm 1:6 is a conjunction the KJV translators used to draw attention to the poetic contrast that would be obvious in the Hebrew reader's mind.
Some translators will strive to preserve the meaning of the text, at the expense of maintaining the feeling of poetry. Consider this translation of Inferno.
Although Dante wrote Italian poetry (with a rhyming scheme), these translators rendered Inferno as English prose.
At some level, the translator is a traitor. See “traduttore, traditore” Do not judge the translators too harshly, lest you be judged.