He shall suck the poison of asps - That which he swallowed as pleasant nutriment, shall become the most deadly poison; or the consequence shall be as if he had sucked the poison of asps. It would seem that the ancients regarded the poison of the serpent as deadly, however, it was taken into the system. They seem not to have been aware that the poison of a wound may be sucked out without injury to him who does it; and that it is necessary that the poison should mingle with the blood to be fatal.
The viper’s tongue shall slay him - The early impression probably was, that the injury done by a serpent was by the fiery, forked, and brandished tongue, which was supposed to be sharp and penetrating. It is now known, that the injury is done by the poison ejected through a groove, or orifice in one of the teeth, which is so made as to lie flat on the roof of the mouth, except when the serpent bites, when that tooth is elevated, and penetrates the flesh. The word “viper” here (אפעה 'eph‛eh), “viper,” is probably the same species of serpent that is known among the Arabs by the same name still - El Effah. See the notes at Isaiah 30:6. It is the most common and venomous of the serpent tribe in Northern Africa and in South-western Asia. It is remarkable for its quick and penetrating poison. It is about two feet long, as thick as a man’s arm, beautifully spotted with yellow and brown, and sprinkled over with blackish specks. They have a large mouth, by which they inhale a large quantity of air, and when inflated therewith, they eject it with such force as to be heard a considerable distance. “Jackson.” Capt. Riley, in his “Authentic Narrative,” (New York, 1817,) confirms this account. He describes the viper as the “most beautiful object in nature,” and says that the poison is so virulent as to cause death in fifteen minutes.