Not to commit any sin, to do good, and to purify one's mind, that is the teaching of (all) the Awakened.
A shared theme
Self-discipline & Inner Life
The one who conquers himself is greater than the one who conquers a city — the Dhammapada, Proverbs and the Tao Te Ching say almost exactly this. Mastery of desire, contentment with enough, and guarding one's speech and thought are the common disciplines.
Buddhism
9 versesChristianity
9 versesA soft answer turneth away wrath: but grievous words stir up anger.
Confucianism
9 versesThe Master said, "The superior man wishes to be slow in his speech and earnest in his conduct."
Hinduism
2 versesALL this, whatsoever moves on earth, is to be hidden in the Lord (the Self). When thou hast surrendered all this, then thou mayest enjoy. Do not covet the wealth of any man!
Islam
5 versesO ye who believe! Fasting is prescribed to you as it was prescribed to those before you, that ye may (learn) self-restraint,-
Jainism
7 verses'Happy are we, happy live we who call nothing our own; when Mithilâ is on fire, nothing is burned that belongs to me.
Judaism
8 versesKeep thy tongue from evil, And thy lips from speaking guile.
Sikhism
7 versesSee the brotherhood of all mankind as the highest order of Yogis; conquer your own mind, and conquer the world.
Sufism
3 versesHe knows not God nor performs His worship who is not contented with his lot. Contentment maketh a man rich—tell this to the avaricious. …
Taoism
1 verseWhen the Tao prevails in the world, they send back their swift horses to (draw) the dung-carts. When the Tao is disregarded in the world, the war-horses breed in the border lands. There is no guilt greater than to sanction ambition; no calamity greater than to be discontented with one's lot; no fault greater than the wish to be getting. Therefore the sufficiency of contentment is an enduring and unchanging sufficiency.
Where the traditions differ
Jain and Buddhist monastic traditions make renunciation the fullest expression of discipline; most Hindu and all Sikh teaching rejects renunciation of the world in favour of discipline within it (the householder path). Islam's fasting and the Christian ascetic tradition sit between. Confucian self-cultivation is social — the disciplined self is the root of the ordered family and state. Taoism's discipline paradoxically looks like letting go. All agree the inner battle is the decisive one.