Ecclesiastes 3:3

“A time to kill, and a time to heal, etc.] A time to kill may be meant of a violent death, as a time to die is of a natural one; so the Targum, “a time to kill in war;” or else, by the hand of the civil magistrate, such who deserve death. Aben Ezra interprets it “to wound”, because of the opposite “to heal”; and so there is a time when wounds and diseases are incurable, and baffle all the skill of the physician, being designed unto death; and there is a time when, by the blessing of God on means, they are healed; the wound or sickness not being unto death: so the Targum paraphrases the last clause, “to heal one that lies sick.” This may be applied in a civil sense to calamities in kingdoms,…”

“time to kill--namely, judicially, criminals; or, in wars of self-defense; not in malice. Out of this time and order, killing is murder. to heal--God has His times for "healing" (literally, Isa 38:5, Isa 38:21; figuratively, Deu 32:39; Hos 6:1; spiritually, Psa 147:3; Isa 57:19). To heal spiritually, before the sinner feels his wound, would be "out of time," and so injurious. time to break down--cities, as Jerusalem, by Nebuchadnezzar. build up--as Jerusalem, in the time of Zerubbabel; spiritually (Amo 9:11), "the set time" (Psa 102:13-16).”

“To kill - When men die a violent death. To heal - When he who seemed to be mortally wounded is healed. Ecclesiastes 3:4”

“time to kill: Deu 32:39; Sa1 2:6, Sa1 2:25; Hos 6:1, Hos 6:2 a time to heal: Num 26:6-9; Isa. 38:5-20; Jer 33:6; Luk 9:54-56; Act 5:15, Act 5:16 a time to break: Isa 5:5, Isa 5:6, Isa 44:26; Jer 31:28, Jer 45:4; Eze 13:14; Dan 9:25-27; Zac 1:12 Ecclesiastes 3:4”

“"To put to death has its time, and to heal has its time; to pull down has its time, and to build has its time." That harog (to kill) is placed over against "to heal," Hitzig explains by the remark that harog does not here include the full consequences of the act, and is fitly rendered by "to wound." But "to put to death" is nowhere = "nearly to put to death," - one who is harug is not otherwise to be healed than by resurrection from the dead, Eze 37:6. The contrast has no need for such ingenuity to justify it. The striking down of a sound life stands in contrast to the salvation of an endangered life by healing, and this in many situations of life, particularly in war, in the administration…”