On courage
Dare
To dare is to lose one’s footing momentarily. Not to dare is to lose oneself.
Courage can mean acting while you are uncertain.
Sources
Søren Kierkegaard · The Sickness Unto Death (1849) · popular paraphrase
The Kierkegaard Research Centre identifies this familiar wording as a paraphrase, not a verbatim quotation. The related passage is in The Sickness Unto Death, SKS 11, p. 150.