Jamieson, Fausset and Brown on Psalms 22:16

16. Evildoers are well described as dogs, which, in the East, herding together, wild and rapacious, are justly objects of great abhorrence. The last clause has been a subject of much discussion (involving questions as to the genuineness of the Hebrew word translated "pierce)" which cannot be made intelligible to the English reader. Though not quoted in the New Testament, the remarkable aptness of the description to the facts of the Saviour's history, together with difficulties attending any other mode of explaining the clause in the Hebrew, justify an adherence to the terms of our version and their obvious meaning.