Now after the death of Jehoiada the leaders of Judah came and bowed down to the king. And the king listened to them."
2 Chronicles 24:2, 17 (NKJV)
We have all seen examples of how one thing influences another; like how the moon affects the ocean's tides. Another example would be how the shining of the sun influences the temperature. But what if somehow the moon no longer had an effect on the ocean or the sun did not shine? The results would not be good. God created things to be interconnected with some things having an effect on other things. Our world is an amazing place when we understand how so many things have an influence on other things and if that influence would be removed negative consequences would follow.
King Joash reigned over Judah for forty years. For a time he did well and followed God, but that only lasted as long as Jehoiada who was the priest at the time was alive. The influence of Jehoiada was seen in how Joash lived and reigned and how that once Jehoiada the priest was gone things changed. Joash went from being a good king to a bad king largely due to the people who influenced him. He did what was good when he had the influence of Jehoiada the priest, but Joash became a bad king once Jehoiada died and Joash even ended up killing the next priest, who was Jehoiada's son!
God created us as individuals and while it is important for us to grow and mature spiritually so that we can stand on our own, we were never meant to live life alone. Even people who are not believers in Jesus are aware that anyone who has no relationships, or only has bad relationships, will not do well. We are all influenced by the people around us and we need to be sure the people we allow into our lives are good, godly people. Christians are a part of the Body of Christ and we should be a positive influence by helping and encouraging one another; we all need to be a good influence on others.