The writer or Hebrews exhorted the church to "stir" each other up. The word for stir is the greek word (paroxusmos) and it literally means to sharpen. Figuratively the word speaks of the sharpening of the mind with incitement to action. The last thing that the church wanted to do was to become stagnate. No one debates today that the physical body needs to have a solid diet. However if you are only well fed without exercise, you become lethargic, apathetic,and unhealthy. What you have taken in, is for the purpose of working it out. I can see this happening in the church.
Sometimes we can simply sit and receive a solid diet of the Word of God without ever having to apply it. But the Lord wants us to receive, in order that we can give. He doesn't want us to be idle but active. I found in my life that there are times when the Lord will stir things up so I don't get stagnate. The Lord may present new challenges and new opportunities in order to help you grow.