I have been working on a commentary on the Psalms. I have decided to compile some of my favorite links that I discovered during my research. There is a mix of exegetical and sermonic links. Here is what I have for Psalm 4 (in no particular order). Feel free to mention any that you find helpful in the comments section.
Spokane Bible Church: http://www.spokanebiblechurch.com/books/psalm-4
Literary analysis of Psalm 4: http://psalmsstudy.com/psalms-chapter-4/literary-analysis-psalm-4
Nancy Koester: https://www.workingpreacher.org/preaching.aspx?commentary_id=3645
Analysis by C. J. Labuschagne: https://www.labuschagne.nl/ps004.pdf
William Barrick’s notes: https://drbarrick.org/files/studynotes/Psalms/Ps_004rev.pdf
“With the King in Prayer” Bruce Waltke: http://www.cslewisinstitute.org/audio/by/title/psalm_4_with_the_king_in_prayer