Sincerity is the starting point of spiritual practice and ethical living. A person’s inner intention goes far towards determining the extent to which his/her particular action is good or evil. The differences in the progress made in the religious life of various people are due to the different levels of sincerity with which they approach the same task.
Through the best righteousness,
Through the highest righteousness,
May we catch sight of Thee,
May we approach Thee,
May we be in perfect friendship with Thee.
Zoroastrianism
Thoughts alone cause the round of births (samsara); let a man strive to purify his thoughts. What a man thinks, that he is: this is an old secret.
By the serenity of his thoughts a man blots out all actions, whether good or bad. Dwelling within his Self with serene thoughts, he obtains imperishable happiness.
If the thoughts of a man were so fixed on Brahman as they are on the things of this world, who would not then be freed from bondage?
The mind, it is said, is of two kinds, pure and impure: impure from the contact with lust, pure when free from lust.
When a man, having freed his mind from sloth, distraction and vacillation, becomes as it were delivered from his mind – that is the highest point.
Hinduism
No matter how dark, the hand always knows the way to the mouth.
African Traditional Religion
Sincerity is the single virtue that binds divinity and man in one.
Shinto
Mind is the forerunner of all evil states. Mind is chief; mind-made are they. If one speaks or acts with wicked mind, because of that suffering follows one, even as the wheel (of the cart) follows the hoof of the draught ox.
Mind is the forerunner of all good states. Mind is chief; mind-made are they. If one speaks or acts with pure mind, because of that happiness follows one, even as one’s shadow that never leaves.
Buddhism
You should worship God as if you saw Him; for although you do not see Him, He sees you.
God does not look at your forms and your possessions, but He looks at your hearts and your deeds.
Islam
It matters not whether you do much or little, so long as your heart is directed to Heaven.
Judaism
A worship without love
And an unfeeling act,
Behold, my brothers, is
A pictured loveliness
No joy in its embrace;
A painted sugarcane No
relish in its taste.
O Lord, without sincerity is no piety.