Adam Clarke's Commentary on the Bible - Job 20:16
He shall suck the poison of asps - That delicious morsel, that secret, easily-besetting sin, so palatable, and so pleasurable, shall act on the life of his soul, as the poison of asps would do on the life of his body. The poison is called the gall of asps, it being anciently supposed that the poison of serpents consists in their gall, which is thought to be copiously exuded when those animals are enraged; as it has been often seen that their bite is not poisonous when they are not angry.... read more
Adam Clarke's Commentary on the Bible - Job 20:15
He shall vomit them up again - This is also an allusion to an effect of most ordinary poisons; they occasion a nausea, and often excruciating vomiting; nature striving to eject what it knows, if retained, will be its bane. read more