Ecclesiastes 12:10

The preacher sought to find out acceptable words: and that which was written was upright, even words of truth.

The preacher is Solomon, the wise preacher. He labored to teach the people knowledge, giving careful attention and searching out and arranging many proverbs, so his teaching was ordered. He diligently and carefully sought acceptable and fitting words in order to instruct and benefit his hearers. What he wrote was upright, straight, and true. His teaching carried the wisdom God gave rather than merely his own power.