Context / meaning
Ecclesiastes 1 [8.] All things are full of weariness beyond uttering. The eye is not satisfied with seeing, nor the ear filled with hearing. That which has been is that which shall be; and that which has been done is that which shall be done: and there is no new thing under the sun. Is there a thing of which it may be said, “Behold,[a] this is new?” It has been long ago, in the ages which were before us. There is no memory of the former; neither shall there be any memory of the latter that are to come, among those that shall come after.
Ecclesiastes 1 [12.] I, the Preacher, was king over Israel in Jerusalem. I applied my heart to seek and to search out by wisdom concerning all that is done under the sky. It is a heavy burden that God[b] has given to the sons of men to be afflicted with. I have seen all the works that are done under the sun; and behold, all is vanity and a chasing after wind.
Ecclesiastes 1 [15.] That which is crooked can’t be made straight; and that which is lacking can’t be counted. I said to myself, “Behold, I have obtained for myself great wisdom above all who were before me in Jerusalem. Yes, my heart has had great experience of wisdom and knowledge.” I applied my heart to know wisdom, and to know madness and folly. I perceived that this also was a chasing after wind. For in much wisdom is much grief; and he who increases knowledge increases sorrow.
a. Ecclesiastes 1:10 “Behold”, from “הִנֵּה”, means look at, take notice, observe, see, or gaze at. It is often used as an interjection.
b. Ecclesiastes 1:13 The Hebrew word rendered “God” is “אֱלֹהִ֑ים” (Elohim).