“Moral excellence comes about as a result of habit. We become just by doing just acts, temperate by doing temperate acts, brave by doing brave acts.”

Misattributed
Variant: We are what we repeatedly do, therefore excellence is not an act, but a habit.
Source: Will Durant, The Story of Philosophy: The Lives and Opinions of the World's Greatest Philosophers (1926), reprinted in Simon & Schuster/Pocket Books, 1991, ISBN 0-671-73916-6], Ch. II: Aristotle and Greek Science; part VII: Ethics and the Nature of Happiness: "Excellence is an art won by training and habituation: we do not act rightly because we have virtue or excellence, but we rather have these because we have acted rightly; 'these virtues are formed in man by his doing the actions'; we are what we repeatedly do. Excellence, then, is not an act but a habit: 'the good of man is a working of the soul in the way of excellence in a complete life... for as it is not one swallow or one fine day that makes a spring, so it is not one day or a short time that makes a man blessed and happy'" (p. 76). The quoted phrases within the quotation are from the Nicomachean Ethics, Book II, 4; Book I, 7. The misattribution is from taking Durant's summation of Aristotle's ideas as being the words of Aristotle himself.

Variant: We are what we repeatedly do. Greatness then, is not an act, but a habit
Source: The Story of Philosophy (1926), p. 87. The quoted phrases within the quotation are from the Nicomachean Ethics, Book II, 4; Book I, 7.
Context: Excellence is an art won by training and habituation: we do not act rightly because we have virtue or excellence, but we rather have these because we have acted rightly; 'these virtues are formed in man by his doing the actions'; we are what we repeatedly do. Excellence, then, is not an act but a habit: 'the good of man is a working of the soul in the way of excellence in a complete life... for as it is not one swallow or one fine day that makes a spring, so it is not one day or a short time that makes a man blessed and happy'.

Source: The Story of Philosophy (1926), p. 87. The quoted phrases within the quotation are from the Nicomachean Ethics, Book II, 4; Book I, 7

Source: Have a Little Faith: a True Story

As quoted in Divine Harmony: The Life and Teachings of Pythagoras by John Strohmeier and Peter Westbrook. (1999)
The Golden Verses

2010-, Never Sorry, 2012

Source: Morals and Dogma of the Ancient and Accepted Scottish Rite of Freemasonry (1871), Ch. XI : Sublime Elect of the Twelve, or Prince Ameth, p. 180
Context: Masonry will do all in its power, by direct exertion and co-operation, to improve and inform as well as to protect the people; to better their physical condition, relieve their miseries, supply their wants, and minister to their necessities. Let every Mason in this, good work do all that may be in his power.
For it is true now, as it always was and always will be, that to be free is the same thing as to be pious, to be wise, to be temperate and just, to be frugal and abstinent, and to be magnanimous and brave; and to be the opposite of all these is the same as to be a slave. And it usually happens, by the appointment, and, as it were, retributive justice of the Deity, that that people which cannot govern themselves, and moderate their passions, but crouch under the slavery of their lusts and vices, are delivered up to the sway of those whom they abhor, and made to submit to an involuntary servitude.
And it is also sanctioned by the dictates of justice and by the constitution of Nature, that he who, from the imbecility or derangement of his intellect, is incapable of governing himself, should, like a minor, be committed to the government of another.
Above all things let us never forget that mankind constitutes one great brotherhood; all born to encounter suffering and sorrow, and therefore bound to sympathize with each other.
For no tower of Pride was ever yet high enough to lift its possessor above the trials and fears and frailties of humanity. No human hand ever built the wall, nor ever shall, that will keep out affliction, pain, and infirmity. Sickness and sorrow, trouble and death, are dispensations that level everything. They know none, high nor low. The chief wants of life, the great and grave necessities of the human soul, give exemption to none.

Source: Steelheart