"Power corrupts." This is a famous saying. To this we may add saying, "absolute power corrupts absolutely." David's sin with Bathsheba (2 Samuel 11) is a typical illustration from the Bible on the corrupting influence of power.
David happens to see Bathsheba, the wife of Uriah, and he wants to make her his wife. But it is not easy even for the king in Israel to take the wife of another person. So, he devises a plan. He was the king and Uriah one of his employees, the best way to possess Uriah's wife is to get him killed. So the king sends Uriah to battle. David also tells his commander to position Uriah in the most vulnerable place where death is sure. And thus he manages to get him killed in the battle! And when the news of Uriah's death was brought to David the king, he makes a stoic comment: "It's Okay, the sword kills both sides." It is natural. David then sends for Bathsheba and she became his wife. The story goes on to say that her son became the next king in Israel after David. A perfect plan: but David would not have done this a few years ago when he had no power.
The David without power was a different person. He was a fugitive for a while; running away from king Saul who was chasing him. One day he had a golden opportunity. He and his enemy who seeks his life happened to be in the same cave. He could have drawn the sword and killed his enemy who was sleeping right in front of him. Instead, he said, "I will not lay hands on the Lord's anointed" and left him there. However, he just cut a piece from Saul's garment to prove that he was very close to him and could have slit his throat open. The Bible says that even that action, that is cutting a piece of his cloth hurt David's conscience. Then he was a fugitive; he had no kingdom, no power and no army. Now the same person who became king would devise a plan to kill an innocent person so that he can possess his wife. In the process he would risk the lives of many other soldiers involved in the battle. In the process he would bring shame upon his countrymen by choosing to lose a battle. It was a match fixing of a sort. Power corrupts, absolute power corrupts absolutely.
How can those who are in leadership protect themselves from the corrupting influence of power? First of all, by realizing that none of us have absolute power. God is ultimate. Secondly, power has corrupting influence on us only when we are too conscious of power. Finally, take power as an opportunity to serve and not to control. Then there would be so much freedom and purity in the use of power.