John Gill Bible Commentary

And all that have not fins nor scales in the seas, and in the rivers,.... Such as eels, lampreys, &c. of all that move in the waters, and of any living thing which is in the waters; the former of these are interpreted by Aben Ezra and Ben Gersom of little fishes that have but a small body, and such as are created out of the waters; and the latter, of such as are produced of a male and female; or, as Maimonides (r) explains it, the one signifies the lesser creatures, such as worms and horse leeches; the other greater ones, sea beasts, as sea dogs, &c. they shall be an abomination to you; not only unclean, and so unfit to eat, but to be had in abhorrence and detestation, as being exceeding disagreeable and unwholesome; and, as a learned man observes (s), to these prohibited in general belong all those animals in lakes, rivers, or seas, which are of a slow motion, and which, because of the slow motion of their bodies, do not so well digest their food; and for that may be compared with four footed beasts that have but one belly, and so unwholesome as they. (r) Hilchot Maacolot Asuret, l. 1. c. 2. sect. 12. (s) Scheuchzer. ut supra, (Physic. Sacr. vol. 2.) p. 287.