Journal entry, Gilleleie (1 August 1835) Journals 1A; this is considered to be one of the earliest statements of existentialist thought.
Variant translation: My focus should be on what I do in life, not knowing everything, excluding knowledge on what you do. The is key to find a purpose, whatever it truly is that God wills me to do; it's crucial to find a truth which is true to me, to find the idea which I am willing to live and die for.
Later variant: What I really lack is to be clear in my mind what I am to do, not what I am to know, except in so far as a certain knowledge must precede every action. The thing is to understand myself, to see what God really wishes me to do: the thing is to find a truth which is true for me, to find the idea for which I can live and die. … I certainly do not deny that I still recognize an imperative of knowledge and that through it one can work upon men, but it must be taken up into my life, and that is what I now recognize as the most important thing.
Later expression of such thoughts in a letter to Peter Wilhelm Lund (31 August 1835)
Variant translation: I must find a truth that is true for me.
1830s, The Journals of Søren Kierkegaard, 1830s
Context: What I really need is to get clear about what I must do, not what I must know, except insofar as knowledge must precede every act. What matters is to find a purpose, to see what it really is that God wills that I shall do; the crucial thing is to find a truth which is truth for me, to find the idea for which I am willing to live and die.