The darkest hour is just before the dawn

It is always darkest just before the Day dawneth.
[1650 T. Fuller Pisgah Sight ii. xi.]

It is usually darkest before day break. You shall shortly find pardon.
[1760 in J. Wesley Journal (1913) IV. 498]

Ayoob Khan now laid siege to Candahar. ‥As so often happens in the story of England's struggles in India, the darkest hour proved to be that just before the dawn.
[1897 1897 J. McCarthy Hist. our Own Times V. iii.]

It is always darkest before the dawn, the old saying goes, and often a declarer reaches a dark point during the early play that precedes his ultimate step toward victory.
[2002 Washington Times 4 Feb. B5]

Related to: hope and despair

Bibliography of major proverb collections and works cited from modern editions is available here.