1 Kings 12:7
The background: After King Solomon's death, his son Rehoboam inherited more than the crown. By dealing with his subjects with a heavy hand during the final years of his reign, Solomon had managed to make enemies within Israel as well as without, in addition to wandering from worship of the one true God. The people were restless, angry and ready to revolt.
A delegation comes to Rehoboam to ask him what kind of king he will be - a delegation fronted by a man named Jeroboam, someone with an ulterior motive. See 1 Kings 11:26 - 40 for his full story, and the reasons he would be happy to see Rehoboam fail.
The delegation has a proposition for the new king: “Your father made our yoke heavy. Now therefore lighten the hard service of your father and his heavy yoke on us, and we will serve you.”
The new king asks for three days to think about his response. He goes to his father's old advisers, and they give him the advice in the verse above. Treat the people well, and they will happily serve the young king.
Great reward can be found in treating people kindly. If Rehoboam had eased the tax burden, improved living conditions and worked to increase the standard of living for all his people, they would have loved him and willingly served him. Over the centuries the terminology used to describe this people management skill has changed, but the principle still holds. If you take care of your people. they will do anything for you.
The principle pops up in the New Testament as well, not only in words, but in the supreme example:
But Jesus called them to him and said, "You know that the rulers of the Gentiles lord it over them, and their great ones exercise authority over them. It shall not be so among you. But whoever would be great among you must be your servant, and whoever would be first among you must be your slave, even as the Son of Man came not to be served but to serve, and to give his life as a ransom for many."
Matthew 20:25 - 28