Ecclesiastes 3:3

3. A time to heal Literally, to save. These verses give opposites, and the opposite of to kill is to save, that is, to save life. The doctrine is, that the loss of life or its preservation, however accidental or otherwise it may seem, is really from the ongoing of fixed law. To this solution the sovereign control of God must all deaths and deliverances come at last.

Break down… build up The vicissitudes of war illustrate this part of the verse. Fortresses are built as a defence, and then destroyed to prevent their sheltering an enemy into whose hands they are likely to fall.