天地不仁，以萬物為芻狗 that's Dao De Jing Chapter 5, I give a try: heaven and earth are not benevolent (I understand) 萬物 all the creatures 為 act 芻狗 grass dogs? dogs playing on grass? dogs made of grass? What to you think? is my translation of the second line in the right direction?
刍狗, is made of grass and used as sacrificial offering, metaphor for humble or useless things.
heaven and earth, i.e. the nature, is not benevolent and partial, it treats all things on the earth the same and fairly.
It just reflects the ideology of
顺其自然(let nature take its course, don't intervene too much).
A Chinese-English Dictionary
straw dogs (used as offerings in ancient sacrifices, brought in with pomp but thrown away afterwards)
天地不仁, 以万物为刍狗；圣人不仁, 以百姓为刍狗。(《道德经》) tiāndì bù rén, yǐ wànwù wéi chú gǒu ； shèngrén bù rén, yǐ bǎixìng wéi chú gǒu. (《Dàodé Jīng》)
Heaven and earth are ruthless, and treat the myriad creatures as straw dogs; the sage is ruthless, and treats the people as straw dogs.
person/thing discarded after use
刍狗 ：dogs made by straws（for sacrifice purpose）。
仁 means favour（prefer）
many people think 仁 means ruth which often appears in Confucius‘s quotes，that's not true。
天地不仁 。。。means heaven and earth don't favour anything，they treat humans and straw dogs in the same way.
圣人不仁。。。 means kings don't favour some of their people more than others，they don't meddle in their affairs。