The Lord killeth - God is the arbiter of life and death; he only can give life, and he only has a right to take it away.
He bringeth down to the grave - The Hebrew word שאול sheol, which we translate grave, seems to have the same meaning in the Old Testament with ἁδης, hades in the New, which is the word generally used by the Septuagint for the other. It means the grave, the state of the dead, and the invisible place, or place of separate spirits. Sometimes we translate it hell, which now means the state of perdition, or place of eternal torments; but as this comes from the Saxon, to cover or conceal, it means only the covered place. In some parts of England the word helling is used for the covers of a book, the slating of a house, etc. The Targum seems to understand it of death and the resurrection. "He kills and commands to give life; he causes to descend into Sheol, that in the time to come he may bring them into the lives of eternity," i.e., the life of shame and everlasting contempt, and the life of glory.

The Lord killeth, and maketh alive,.... Which is true of different persons; some he takes away by death, and others he preserves and continues in life; and of the same persons, whom God removes by death, and restores them to life again, of which there are instances both in the Old and New Testament; and be they which they will, both are of God, he is the great Disposer of life and death. Death is of him; it is by his appointment; it is sent by his order; and when it has a commission from him, there is no resisting it; and let it be brought about by what means it will, still it is of God: and life is of him; it is first given by him, and it is preserved by him; and though taken away, it shall be restored at the resurrection of the dead; of which some interpret this clause, as Kimchi and Ben Gersom observe: and what is here said is true, in a spiritual sense; the Lord kills by the law, or shows men that they are dead in sin, and in a legal sense; and he makes alive by his Spirit, through the Gospel, quickening such who were dead in trespasses and sins; which is his own work, and the effect of divine power and grace; See Gill on Deuteronomy 32:39.
he bringeth down to the grave, and bringeth up; he bringeth some very near to the grave, to the very brink of it; so that in their own apprehensions, and in the opinion of their friends, they are just dropping into it, and no hope of recovery left; when he says to them "Return", and brings them back from the pit, and delivers them from going into it, Job 33:22 and even when they are laid in it, he brings up out of it again, as in the case of Lazarus, and which will be the case in the resurrection, John 5:28.

he bringeth down to the grave, and bringeth up--that is, He reduces to the lowest state of degradation and misery, and restores to prosperity and happiness.

Killeth - The same person whom he first killeth, or bringeth nigh unto death, he afterwards raiseth to life. Me, who was almost consumed with grief, he hath revived. The name of death both in sacred scripture, and profane writers, is often given to great Calamities.