What the expression "Bien mal acquis ne profite jamais" means is that : a good (=bien) that's been obtained (=acquis) in an unfair way (=mal) never (=ne...jamais) profits (=profite).

"One should not profit from the sale of stolen goods" would be "Il ne faut pas profiter de la vente de biens volés" whereas "It's unfair to profit from selling items that have been stolen" would be "Il est mal de profiter de la vente d'objets qui ont été volés". It's in the other way, in fact.

The object that is unfairly obtained never profits. I am sure of the meaning but not of the english syntax.

Oww.. I understand what you find strange, it's the fact that the object "profits" !

In French, we can say that ; and that means that the object brings "more" to its owner.

If I say "Mes cours d'anglais m'ont profité", that means that my english lessons have brought more (english knowledge) to me.

I don't know how to express it naturally in english.

2Jio15
I wonder if you're trying to say something like "Ill-gotten goods never prosper".

The traduction of sharptoothed means exactly what it means in French ! I'll correct with "ill-gotten gains never benefit anyone".