'Alone' in the Bible

He has made everything beautiful and appropriate in its time. He has also planted eternity [a sense of divine purpose] in the human heart [a mysterious longing which nothing under the sun can satisfy, except God]—yet man cannot find out (comprehend, grasp) what God has done (His overall plan) from the beginning to the end.

There is one alone, and there is not a second; yea, he hath neither child nor brother: yet is there no end of all his labour; neither is his eye satisfied with riches; neither saith he, For whom do I labour, and bereave my soul of good? This is also vanity, yea, it is a sore travail.

For if they fall, the one will lift up his fellow: but woe to him that is alone when he falleth; for he hath not another to help him up.

Again, if two lie together, then they have heat: but how can one be warm alone?

And if one can overpower him who is alone, two can resist him. A cord of three strands is not quickly torn apart.

See, this alone I have found, that God made man upright, and they -- they have sought out many devices.