'Sad' in the Bible

And I have given my heart to seek and to search out by wisdom concerning all that hath been done under the heavens. It is a sad travail God hath given to the sons of man to be humbled by it.

And I have hated life, for sad to me is the work that hath been done under the sun, for the whole is vanity and vexation of spirit.

There is one, and there is not a second; even son or brother he hath not, and there is no end to all his labour! His eye also is not satisfied with riches, and he saith not, 'For whom am I labouring and bereaving my soul of good?' This also is vanity, it is a sad travail.

Grief is better than laughter,for when a face is sad, a heart may be glad.