What did a person look like after being beaten 39 times?
The context states that in our modern age we can have no concept of what a human being looked like after being beaten 39 times. Few victims could endure that many, as most men would die during the whipping, and the highest authority often had to stop the whipper before that point.
Les explains that very few victims could take that many lashes; the chief priest or highest authority would often have to stop the whipper before reaching 39 because most men couldn't endure it and would die during the whipping. He notes that we in our modern age can have no concept of what a human being looked like after being beaten 39 times. He also contrasts this with stoning, which was even worse: when Jews stoned someone, using rocks so big it took two hands to smash down, the corpse was obscene, literally pummeled. The Apostle Paul went through this, and Les reminds us that in our western culture most have never suffered for their faith, yet this is what the man had to go through to give us our New Testament.