'Someone' in the Bible

So I hated all my toil with which I have toiled under the sun, for I must leave it behind to someone who will be after me.

For although a person may toil with great wisdom and skill, he must leave his reward to someone who has not toiled for it. This also [is] vanity and a great calamity.

God gives a man wealth, possessions, and honor, so that he lacks nothing his heart desires; yet God does not enable him to enjoy it--instead someone else ends up enjoying it. This [is] vanity--indeed, it [is] a grievous ill!