He 'profited by' his experience/mistake. [=he learned something useful from his experience/mistake]
The book can be read with 'profit' by anyone who wants to understand how the system works.
We sold the house 'at a profit'. [=we made a profit when we sold our house]
(..) I won't hurt you. I will love you. Brother. When we reach Kattegat, Bjorn Ironside will take all the profits from these women. So he will. For now. And who is this? I didn't know him either. Turns out his father is an Earl. An Earl? (..)2017 TvShow: Vikings Title: The Great Army Season: 4 Episode 17