“Rest” in the Bible is more than simple relaxation from a hard day’s work. Rest is God’s complete provision for us as a people. It is wholistic. This is the rest that Naomi is seeking for Ruth in chapter three. She wants to ensure that Ruth will be fully provided.
In the same manner, God is our rest. Just as Naomi believed Boaz would be the one to provide rest for Ruth, we are called to believe that the greater Boaz will provide rest for us (Matthew 6).