But thou, O God, shalt bring them down into the pit of destruction - The Chaldee is emphatic: "And thou, O Lord, by thy Word (במימרך bemeymerach ) shalt thrust them into the deep gehenna, the bottomless pit, whence they shall never come out; the pit of destruction, where all is amazement, horror, anguish, dismay, ruin, endless loss, and endless suffering."
Bloody and deceitful men shall not live out half their days - So we find, if there be an appointed time to man upon earth, beyond which he cannot pass; yet he may so live as to provoke the justice of God to cut him off before he arrives at that period; yea, before he has reached half way to that limit. According to the decree of God, he might have lived the other half; but he has not done it.
But I will trust in thee - Therefore I shall not be moved, and shall live out all the days of my appointed time.
The fathers in general apply the principal passages of this Psalm to our Lord's sufferings, the treason of Judas, and the wickedness of the Jews; but these things do not appear to me fairly deducible from the text. It seems to refer plainly enough to the rebellion of Absalom. "The consternation and distress expressed in Psalm 55:4-8, describe the king's state of mind when he fled from Jerusalem, and marched up the mount of Olives, weeping. The iniquity cast upon the psalmist answers to the complaints artfully laid against the king by his son of a negligent administration of justice: and to the reproach of cruelty cast upon him by Shimei, 2 Samuel 15:2, 2 Samuel 15:4; 2 Samuel 16:7, 2 Samuel 16:8. The equal, the guide, and the familiar friend, we find in Ahithophel, the confidential counsellor, first of David, afterwards of his son Absalom. The buttery mouth and oily words describe the insidious character of Absalom, as it is delineated, 2 Samuel 15:5-9. Still the believer, accustomed to the double edge of the prophetic style, in reading this Psalm, notwithstanding its agreement with the occurrences of David's life, will be led to think of David's great descendant, who endured a bitter agony, and was the victim of a baser treachery, in the same spot where David is supposed to have uttered these complaints." - Bishop Horsley.
But thou, O God, shalt bring them down into the pit of destruction - The word “them,” here evidently refers to the enemies of the psalmist; the wicked people who were arrayed against him, and who sought his life. The “pit of destruction” refers here to the grave, or to death, considered with reference to the fact that they would be “destroyed” or “cut off,” or would not die in the usual course of nature. The meaning is, that God would come forth in his displeasure, and cut them down for their crimes. The word “pit” usually denotes “a well,” or “cavern” Genesis 14:10; Genesis 37:20; Exodus 21:34, but is often used to denote the grave (Job 17:16; Job 33:18, Job 33:24; Psalm 9:15; Psalm 28:1; Psalm 30:3, Psalm 30:9, et al.); and the idea here is that they would be cut off for their sins. The word “destruction” is added to denote that this would be by some direct act, or by punishment inflicted by the hand of God.
Bloody and deceitful men - Margin, as in Hebrew, “Men of bloods and deceit.” The allusion is to people of violence; people who live by plunder and rapine; and especially to such people considered as false, unfaithful, and treacherous - as they commonly are. The special allusion here is to the enemies of David, and particularly to such as Ahithophel - men who not only sought his life, but who had proved themselves to be treacherous and false to him.
Shall not live out half their days - Margin, as in Hebrew, “shall not halve their days.” So the Septuagint, and the Latin Vulgate. The statement is general, not universal. The meaning is, that they do not live half as long as they might do, and would do, if they were “not” bloody and deceitful. Beyond all question this is true. Such people are either cut off in strife and conflict, in personal affrays in duels, or in battle; or they are arrested for their crimes, and punished by an ignominious death. Thousands and tens of thousands thus die every year, who, “but” for their evil deeds, might have doubled the actual length of their lives; who might have passed onward to old age respected, beloved, happy, useful. There is to all, indeed, an outer limit of life. There is a bound which we cannot pass. That natural limit, however, is one that in numerous cases is much “beyond” what people actually reach, though one to which they “might” have come by a course of temperance, prudence, virtue, and piety.
God has fixed a limit beyond which we cannot pass; but, wherever that may be, as arranged in his providence, it is our duty not to cut off our lives “before” that natural limit is reached; or, in other words, it is our duty to live on the earth just as long as we can. Whatever makes us come short of this is self-murder, for there is no difference in principle between a man‘s cutting off his life by the pistol, by poison, or by the halter, and cutting it off by vice, by crime, by dissipation, by the neglect of health, or by those habits of indolence and self-indulgence which undermine the constitution, and bring the body down to the grave. Thousands die each year whose proper record on their graves would be “self-murderers.” Thousands of young people are indulging in habits which, unless arrested, “must” have such a result, and who are destined to an early grave - who will not live out half their days - unless their mode of life is changed, and they become temperate, chaste, and virtuous. One of the ablest lawyers that I have ever known - an example of what often occurs - was cut down in middle life by the use of tobacco. How many thousands perish each year, in a similar manner, by indulgence in intoxicating drinks!