“Always be mindful, one has complete authority over psyche, words, and actions. Deliberative judgment of these three things, determine your station in life.”
1982
Related quotes

“Always rely on the power of your actions. They will determine the course of your days.”
Original: (it) Affidati sempre al potere delle tue azioni. Saranno loro a determinare il corso delle tue giornate.
Source: prevale.net

“Your action, and your action alone, determines your worth.”
Johann Gottlieb Fichte in The Vocation of Man [Die Bestimmung des Menschen] (1800), p. 94 : "You are here, not for idle contemplation of yourself, not for brooding over devout sensations — no, for action you are here; action, and action alone, determines your worth." [Nicht zum müßigen Beschauen und Betrachten deiner selbst, oder zum Brüten über andächtigen Empfindungen, — nein, zum Handeln bist du da; dein Handeln und allein dein Handeln bestimmt deinen Werth.]
Misattributed
Source: "Price and production policies of large-scale enterprise," 1939, p. 61

[http://www.jfklibrary.org/Research/Research-Aids/Ready-Reference/JFK-Quotations.aspx "President's News Conference (107)" (21 March 1962)
1962