Indeed you are to them as a very lovely song of one who has a pleasant voice and can play well on an instrument; for they hear your words, but they do not do them."
Ezekiel 33:31-32 (NKJV)
When you agree with someone about something, that means that there is harmony between you and the other person about that thing; when you take action, you are doing something. There can, and often is, action when there is agreement, but that is not always true. Someone can agree that having a healthy lifestyle is a good thing and never eat right or exercise. It is best when there is action involved with an agreement, otherwise the agreement may only be a theoretical opinion.
God spoke through Ezekiel to the people of Israel. The people listened to Ezekiel, but they did not do the things that God was saying to them through Ezekiel. God said that the situation was like people who listen to a song, and they hear the nice words, but that is the end of it. In James 1:22, it says we need to be a doer of the Word and not just someone who hears the Word. That was the problem with the people who listened to Ezekiel, they heard what he said, and even seemed to agree with it, but they did not act on it.
Today, there are many people who are hearing God's Word, and they may agree with it, but they are not doing the things that God's Word says. The result is that people are not living the kind of life that God is calling them to, they are not doing the things God asks them to do, and they are not taking advantage of everything God did for us through Jesus. We need to be people who hear God's Word, put ourselves in agreement with it, and then we put action to what we have heard.