'Son' in the Bible

The words of the Preacher, the son of David, king in Jerusalem.

It is one who is by himself, without a second, and without son or brother; but there is no end to all his work, and he has never enough of wealth. For whom, then, am I working and keeping myself from pleasure? This again is to no purpose, and a bitter work.

And I saw the destruction of his wealth by an evil chance; and when he became the father of a son he had nothing in his hand.

And further, my son, take note of this: of the making of books there is no end, and much learning is a weariness to the flesh.