He had spoken before of those that devoured the poor (Pro 30:14), and had spoken of them last, as the worst of all the four generations there mentioned; now here he speaks of their insatiableness in doing this. The temper that puts them upon it is made up of cruelty and covetousness. Now those are two daughters of the horse-leech, its genuine offspring, that still cry, "Give, give, give more blood, give more money;" for the bloody are still blood-thirsty; being drunk with blood, they add thirst to their drunkenness, and will seek it yet again. Those also that love silver shall never be satisfied with silver. Thus, while from these two principles they are devouring the poor, they are continually uneasy to themselves, as David's enemies, Psa 59:14, Psa 59:15. Now, for the further illustration of this, I. He specifies four other things which are insatiable, to which those devourers are compared, which say not, It is enough, or It is wealth. Those are never rich that are always coveting. Now these four things that are always craving are, 1. The grave, into which multitudes fall, and yet still more will fall, and it swallows them all up, and returns none, Hell and destruction are never full, Pro 27:20. When it comes to our turn we shall find the grave ready for us, Job 17:1. 2. The barren womb, which is impatient of its affliction in being barren, and cries, as Rachel did, Give me children. 3. The parched ground in time of drought (especially in those hot countries), which still soaks in the rain that comes in abundance upon it and in a little time wants more. 4. The fire, which, when it has consumed abundance of fuel, yet still devours all the combustible matter that is thrown into it. So insatiable are the corrupt desires of sinners, and so little satisfaction have they even in the gratification of them. II. He adds a terrible threatening to disobedient children (Pro 30:17), for warning to the first of those four wicked generations, that curse their parents (Pro 30:11), and shows here, 1. Who they are that belong to that generation, not only those that curse their parents in heat and passion, but, (1.) Those that mock at them, though it be but with a scornful eye, looking with disdain upon them because of their bodily infirmities, or looking sour or dogged at them when they instruct or command, impatient at their checks and angry at them. God takes notice with what eye children look upon their parents, and will reckon for the leering look and the casts of the evil eye as well as for the bad language given them. (2.) Those that despise to obey them, that think it a thing below them to be dutiful to their parents, especially to the mother, they scorn to be controlled by her; and thus she that bore them in sorrow in greater sorrow bears their manners. 2. What their doom will be. Those that dishonour their parents shall be set up as monuments of God's vengeance; they shall be hanged in chains, as it were, for the birds of prey to pick out their eyes, those eyes with which they looked so scornfully on their good parents. The dead bodies of malefactors were not to hang all night, but before night the ravens would have picked out their eyes. If men do not punish undutiful children, God will, and will load those with the greatest infamy that conduct themselves haughtily towards their parents. Many who have come to an ignominious end have owned that the wicked courses that brought them to it began in a contempt of their parents' authority.