“Familiar habit makes for indolence.”

Anti-Goeze (1778), as quoted in God Is Not Great (2007), by Christopher Hitchens , Ch. 19
Context: The true value of a man is not determined by his possession, supposed or real, of Truth, but rather by his sincere exertion to get to the Truth. It is not possession of the Truth, but rather the pursuit of Truth by which he extends his powers and in which his ever-growing perfectibility is to be found. Possession makes one passive, indolent, and proud. If God were to hold all Truth concealed in his right hand, and in his left only the steady and diligent drive for Truth, albeit with the proviso that I would always and forever err in the process, and offer me the choice, I would with all humility take the left hand, and say: Father, I will take this one—the pure Truth is for You alone.

Book Sometimes you win Sometimes you Learn

In this work are exhibited in a very high degree the two most engaging powers of an author. New things are made familiar, and familiar things are made new. ~ Samuel Johnson, "The Life of Alexander Pope" from Lives of the English Poets (1781) http://www.gutenberg.org/dirs/etext04/lvpc10.txt
Misattributed

A Defence of Poetry http://www.bartleby.com/27/23.html (1821)

Book II, line 647 (tr. James Michie)
Ars Amatoria (The Art of Love)

Source: White-Jacket (1850), Ch. 23
Context: Familiarity with danger makes a brave man braver, but less daring. Thus with seamen: he who goes the oftenest round Cape Horn goes the most circumspectly.