Philemon
Introductory Course:
Click here:
https://www.thegospelcoalition.org/course/philemon/
In-Depth Course: Twelve Week Bible Study:
Click here:
https://www.thegospelcoalition.org/course/knowing-bible-colossians-philemon/
Both Courses Provided by: The Gospel Coalition
https://en.wikipedia.org/wiki/The_Gospel_Coalition
Alistair Begg: Sermons from Philemon
https://blog.truthforlife.org/sermons-from-philemon-by-alistair-begg
David Strain: Expository Teaching from Philemon