The KJV misses all the philosophically interesting points here. This statement isn't clearly positive or negative.  First, there is the sense that a "soul" is acquired. Second, while all the other nouns and verbs here are plural, the "soul" or "ego" is singular. There is only one that we can all acquire. All the key words are translated oddly to conform to a certain dogma that the verse doesn't support.

The word translated as "in" also means "within", "with," or "among."

The word translated as "your" is plural addressing a group of Jesus's listeners. It follows the noun, which is optional and so intentional,  so "of yours" is more correct.

"Patience" is an  uncommon word, a noun meaning, "remaining beautiful", " endurance",  in bad sense, "obstinacy", of plants, "power to endure", and "enduring to do". "Endurance" is a better translation than "patience". This word is used to describe the ability of plants to endure, which we would call "hardiness". 

The term translated as "possess ye" means "to acquire," but specifically for yourself. It also means "to possess" in the sense of having something stored in opposition to the common Greek word that means "possess" in the sense of having it in hand. So the sense is either that a ego is found stored within your endurance or that you acquire it by endurance. This is in the future tense.

The word translated as "your" is plural addressing a group of Jesus's listeners. It follows the noun, which is optional and so intentional,  so "of yours" is more correct. 

The word translated here as "souls" is singular, psyche, a common word in Greek, familiar in English, meaning "life", "soul", "consciousness," and "a sense of self." Jesus uses it to specifically mean our identity in our worldly life, the role we play on earth, what we commonly call our "ego", not the soul that lives after death. See this article for detail about this word and related words.