7 year old boy hearing troubling voices

My son is 7, soon to be 8 and about 5 months ago or so, at bed time, he told me he had a hard time getting to sleep because had been hearing voices, and they bothered him. He said the voices tell him that he should...hurt or kill himself- the main thing I remember is voices, and that they were not saying good things. Frankly, I find it difficult to believe I'm even writing this- it is hard to believe he uttered those words and that I haven't done more by now. There is no other indication that there is anything wrong- behavioral or otherwise.
I told him to think of his favorite things and let the voices know he's not interested in them. I made a point of not making an issue of it around him to see what happened- if he mentioned the voices again. As I recall, he mentioned them again once a few days, or a week or so later, and I asked how thinking of his favorite things worked in making them go away, and he seemed to be pleased with how that worked. This didn't come up again until I asked about it, again, probably a few weeks later and he said he still heard them- but he didn't make much of them and again, I wanted to see if it was real or...or something else- his way of reacting to things he's unhappy about, and if this would pass. I don't recall if I asked him when he heard them most or too many other particulars.
He didn't mention them again until the other day (4 months later). He said they’re telling him to kill God, and when I asked why he hadn’t said anything about them for a while, he said he didn't want to mention them because...he didn't want to draw attention to them. It seems pretty clear to me that he should see a psychologist, but I'm interested to hear any advice from professionals out there as to what I can do- even in the mean time.

[margypops]

Does he watch anything that may disturb him or be graphic, on TV or Computer, are they supervised, has he any older siblings or family who may discuss scary 'stuff' within his earshot?If it continues it may be a good idea to speak to yo0ur doctor and see what he thinks about it.Good Luck