I agree with you here, Dr. Duguid. Neither exclusive Psalmody nor an inclusive practice can be proven from that passage alone. The terms admit of various usages. To my mind the key question is whether God has commanded us to sing songs that he hasn't given us by inspiration. If it can be proven that he has, then the hymn-singer has his case. If it cannot be proven, then we are limited to inspired praise, for all sides (in our circles, anyway) admit that inspired praise is to be sung. From that point, the question of which inspired songs God has prescribed can be dealt with (I'm quite fond of the old ditty With the Jaw Bone of an Ass, but I wouldn't suggest it be sung in worship).