'Themselves' in the Bible

And I applied my heart to seek and search out by wisdom concerning all that is done under the heavens: this grievous occupation hath God given to the children of men to weary themselves therewith.

I said in my heart, It is thus with the children of men, that God may prove them, and that they should see that they themselves are but beasts.

If the clouds be full of rain, they empty themselves upon the earth; and if a tree fall toward the south, or toward the north, in the place where the tree falleth, there it shall be.

in the day when the keepers of the house tremble, and the strong men bow themselves, and the grinders cease because they are few, and those that look out of the windows are darkened,