“So, keep your powder dry and dig in for a long, fruitful life of being a writer, that storyteller around the campfire of your people and your generation. Your trade is as old as time, and your main job is to uplift the human heart so that then we can go on with dignity and fair play. That’s it”

Attributed by William Blacker (not to be confused with Valentine Blacker), who popularized the quote with his poem "Oliver's Advice" http://books.google.com/books?id=JmEaAQAAIAAJ&dq=%22Oliver%27s+Advice%22+Cromwell&q=%22Oliver%27s+Advice%22+Cromwell#v=snippet&q=%22Oliver's%20Advice%22%20Cromwell&f=false, published under the pseudonym Fitz Stewart in The Dublin University Magazine, December 1834, p. 700; where the attribution to Cromwell appears in a footnote describing a "well-authenticated anecdote" that explains the poem's title. The repeated line in Blacker's poem is "Put your trust in God, my boys, but keep your powder dry".
Attributed
Variant: Trust in God and keep your powder dry.
Variant: Put your trust in God, but keep your powder dry.

From the poem "Oliver's Advice" http://books.google.com/books?id=JmEaAQAAIAAJ&dq=%22Oliver%27s+Advice%22+Cromwell&q=%22Oliver%27s+Advice%22+Cromwell#v=snippet&q=%22Oliver's%20Advice%22%20Cromwell&f=false by William Blacker, published under the pseudonym Fitz Stewart in The Dublin University Magazine, December 1834, p. 700. This line by a different Colonel Blacker is paraphrased from an attribution to Oliver Cromwell (hence the poem's title).
Misattributed

"Fiddler Jones"

Unsourced

Disputed
Context: So live your life that the fear of death can never enter your heart. Trouble no one about their religion; respect others in their view, and demand that they respect yours. Love your life, perfect your life, beautify all things in your life. Seek to make your life long and its purpose in the service of your people. Prepare a noble death song for the day when you go over the great divide. Always give a word or a sign of salute when meeting or passing a friend, even a stranger, when in a lonely place. Show respect to all people and grovel to none. When you arise in the morning give thanks for the food and for the joy of living. If you see no reason for giving thanks, the fault lies only in yourself. Abuse no one and no thing, for abuse turns the wise ones to fools and robs the spirit of its vision. When it comes your time to die, be not like those whose hearts are filled with the fear of death, so that when their time comes they weep and pray for a little more time to live their lives over again in a different way. Sing your death song and die like a hero going home.

As quoted in A Sourcebook for Earth's Community of Religions (1995) by Joel Diederik Beversluis; but also ascribed to some of the Wabasha chiefs, Sitting Bull, Crazy Horse and Wovoka, according to Ernest Thompson Seton, The Gospel of the Red Man: An Indian Bible, San Diego, The Book Tree, 2006, p. 60

Source: Incubus Dreams