You're speaking of emotions, not jin in the sense of power. Of course there's the jin, or ching, of emotions, the feng ching (the name from our nomenclature). Easier called emotions, like hate, joy, anger, fear, etc. That's persistent, and it is there until recycled. A feeling of bad intention, that is not softened with good, keeps worrying, but it's only wrong if it has wrong ideas. A hard feeling of power, that wants to oppose, instead, what usually is named the yin approach, blend, is good in the sense of helpful when the action of someone is on the way. I learned that it has a good effect when you stop the attack with high level of jin output that indicates the attacker there is some unusual amount of force that could and will shatter him, and speak to him AFTER this. Start to speak first, and it might be difficult. The negative is not in the power, the qi, it's the emotion driving. It depends entirely on how balanced the emotion is if it is okay, or not. It's a good teaching to show someone who abuses force what it feels like when force is used on him, when you afterwards lend the helping hand. You can transfer feng ching, creating emotions in someone, which is what usually happens when you see a small child and feel love, but you cannot transfer good or bad qi with hammering someone. The good or bad qi is a myth, the "good" intention driven will not overcome bad one if the bad guy is stronger, and your soul is not intervening with extreme levels of smartness. But the capability of the soul to intervene is there, it can simply stop the bad guy from using his power. It's just different what the soul decides would solve it best, sometimes it makes you walk off the place.

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"Fawning, but proud!" - (at least sometimes, in rare cases)
"Killing them all didn't make it any better..." - "Are you a freak or something ???" - Max Payne
"Theft is a crime, even in Iraq." - Me.