“Tiredness and fatigue are effects caused by ignorance of Nature and disobedience to her inexorable law. You may command Nature to the extent only in which you are willing to obey her. You cannot intelligently obey that which you do not comprehend. Ask of Nature that you may be one with her and she will whisper her secrets to you to the extent in which you are prepared to listen. Seek to be alone much to commune with Nature and be thus inspired by her mighty whisperings within your consciousness. Nature is a most jealous god, for she will not whisper her inspiring revelations to you unless you are absolutely alone with her.”

Viktor Schauberger: Our Senseless Toil (1934)

In the article 'What I know about women...' in Observer Women's Magazine (February 2007)
Context: When I was about 15, thinking I was engaging in a light conversation, I asked a woman when she was due. Of course, she wasn't pregnant. I learned the lesson never to ask again. As a leading man you don't ask a woman's age, and you don't care about her natural hair colour or her weight.

“While it is in the nature of Law,” Alisaard explained, “to be forever fixed. The Balance is there to ensure that neither Law nor Chaos ever gain complete ascendancy, for the one offers sterility while the other offers only sensation.”
Book 3, Chapter 1 (p. 626)
Erekosë, The Dragon in the Sword (1986)

Source: Devil's Cub

Variant: You may not be her first, her last, or her only. She loved before she may love again. But if she loves you now, what else matters? She's not perfect — you aren't either, and the two of you may never be perfect together but if she can make you laugh, cause you to think twice, and admit to being human and making mistakes, hold onto her and give her the most you can. She may not be thinking about you every second of the day, but she will give you a part of her that she knows you can break — her heart. So don't hurt her, don't change her, don't analyze and don't expect more than she can give. Smile when she makes you happy, let her know when she makes you mad, and miss her when she's not there.

Source: The poem was originally titled "Habe Geduld". It was first published in Blüthen des Herzens around 1906. https://www.bartfmdroog.com/droog/dd/bluthen_des_herzens_scans.html#front

Adolf Hitler used this poem with the title "Deine Mutter" in the handwritten manuscript he signed and dated in 1923. For this reason, this poem is sometimes misattributed to him. Adolf Hitler, "Denk' es!" (Be Reminded!) 1923, first published in Sonntag-Morgenpost (14 May 1933).

Source: Ivanhoe (1819), Ch. 23.

RODIN, AUGUSTE. L'Art. Entretiens réunis par Paul Gsell, 1911

Source: If You Dare