Does our state effect our ability to heal? If we are gossiping, jealous, backstabbing, deceitful, dishonest, lack integrity, basically are "unclean" in the Jewish sense, or "living in sin" in the Christian sense, does that effect our ability to heal? That depends. Does the healing come from you, or from somewhere else? Are you a vessel for it, or do you just point where it should go?
Why do I say it depends? Is it really different if we are the vessel or if we aren't? In order to answer that, I will need to approach it from the theoretical side, because the experiential, mystical, and spiritual side gets a bit messy. As always, these are my thoughts and opinions.
To be able to discuss it, I'll use the terms "instrument", "vessel", and "source". These describe three possible ways healing, or magic, might work. In practice, I think it's usually all three, but that gets messy. If the healer (or practitioner of magic is general) determines what needs to be done, then asks the source (deity, spirit, object, etc.) to perform the healing, and nothing passes through the healer except the request, we will call the healer the instrument. She's like a compass that tells us where north is, a thermometer that determines the temperature, a sextant that determines the height of the sun. The instrument doesn't actually create any change, meerly measures and determines need. If the healing power flows through the healer, we will call the healer a vessel (conduit would be a good word as well). He becomes like the cup the tea is given to the patient in. The power comes from the source into the vessel, then into the recipient. If the power is inherent in the healer, the healer is the source. All healing, all magic, has a source. "Energy cannot be created or destroyed." That can be the healer herself, or it can be an object of power (this is common in hoodoo and conjure, though it may be a spirit tied to the object), or it could be a spirit or deity. And sometimes it can be another human, or an animal. Mongolian and Siberian shamans have as their sources both spirits of the dead, and animal spirits. If it is the healer himself, he is the source.
Ok, now that we have some terms to use, let's look at each one in relation to the original question.
If the healer is an instrument, no power passes through her, so clean or not, regardless of what else, the energy can't be tainted. The source might not choose to work with the instrument because of some impurity or uncleanness, but it doesn't effect the healing itself, there just is no healing in that case.
If the healer is the vessel, there is potential to effect the power you are using. This is much like how a prophet or oracle or medium delivers the message in their own words quite often. The vessel alters the energy. So, in this case, impurities or uncleanness could potentially effect the healing directly. It's like a stream flowing through a rock formation, picking up trace amounts of minerals and washing them downstream.
If the healer is the source, all the power is coming directly from them. If you drink from a healthy, flowing stream, it is usually safe (or was in the time before giardia and similar organisms). Drinking from a stagnant pond will usually get you killed, unless you're lucky.
An instrument has the least personal impact on the healing, and the source has the most impact. So, that's why say it's a different issue whether we are vessels or something different.
However, the next question is, does it actually matter? Can someone without integrity, who isn't honest, who gossips, who is jealous, who "sins" and is "unclean" still heal, even if they are the source or the vessel? I think so. If you read accounts in history and folklore, there are examples of pretty nasty characters healing people. It might be interesting to ask the question, can a poisoned chalice heal?
Poisons are very interesting to me. I know of no naturally occurring poison that can't be used to heal as well as harm. Aconite is nasty as a poison, but small amounts can cure many things. Deadly nightshade can also be used both to heal and to hurt. Or take blackthorn, always thought of in terms of cursing and harm, the thorns causing bad infections, the traditional use in shillelaghs. Yet the alcohol made from the berries is said to heal almost everything.
There are basically two ways to do magic. You can bind or you can loose. You can curse or you can bless. Both ways can be used to do the same thing, if you're clever and cunning. In healing, you can either bless (improve the patient's ability to fight off the infection or to heal the damage) and loose (release the patient from the illness), or you can curse (kill the infection) and bind (hold back the infection or attacker to give room to heal). It is hard to bless and loose from darkness, and hard to heal and bind from light. But we both have both in us, as do all things, the Twins in the Great Dance, Shining Bright One and Shadowy Darkling. We can use our darkness, our impurities, our demons to heal, just as much as we can use our light, our purity, our innocence, our angels.
That's my opinion anyway.
FFF,
~Muninn's Kiss