In Ecclesiastes 3:10, the same 'burden God has laid on human beings' echoes the 'unhappy business' from 1:13, reinforcing the theme of divinely appointed toil.

Ecclesiastes 7:25 echoes this same pursuit of wisdom through exploration.

Ecclesiastes 8:16 continues with 'I applied my mind to know wisdom and observe labor,' mirroring the same investigative effort and its toll.

Ecclesiastes 8:17 concludes that no one can comprehend God's work — the futility hinted at here in the 'unhappy business' is fully stated.

In Ecclesiastes 12:12, 'much study wearies the body' directly connects to the wearying search for wisdom described in 1:13.

In Ecclesiastes 2:18, the exploration from 1:13 leads to hating toil because it will be left to an heir — the heavy burden's outcome.

In Ecclesiastes 4:4, envy-driven toil illustrates one specific form of the 'unhappy business' — human labor springing from competition.

In Ecclesiastes 4:8, a solitary toiler illustrates the heavy burden from 1:13 — meaningless labor with no one to inherit.

Proverbs 2:2-4 urges seeking wisdom like hidden treasure, echoing the search here but with a positive, urgent tone.

Proverbs 18:15 says the discerning heart acquires knowledge and the wise seek it, directly paralleling the Preacher's pursuit.

In 1 Kings 3:12, God grants Solomon a wise and discerning heart — the very wisdom he later uses to explore all things under heaven in 1:13.

In Genesis 3:17, the curse on the ground leading to painful toil is the backdrop for the burdensome task described in 1:13.

In Genesis 3:19, the curse of sweat-of-brow labor provides the origin story for the 'unhappy business' God gave humans.

Psalm 111:2 portrays pondering God's works as delightful, a stark contrast to the 'unhappy business' of Ecclesiastes 1:13.

In Job 28:3, humans search the darkness for ore — paralleling the search by wisdom, though Job concludes wisdom is not found by such effort.

Proverbs 4:7 commands 'Get wisdom, though it cost all you have,' affirming wisdom's supreme value despite the cost implied here.