Mark 11:23
23 For verily I say unto you, That whosoever shall say unto this mountain, Be thou removed, and be thou cast into the sea; and shall not doubt in his heart, but shall believe that those things which he saith shall come to pass; he shall have whatsoever he saith.
Your believer is a great generator of power. Like the giant generators that supply energy to cities, your believer is a generator that supplies energy for your life. It is like a giant dynamo that unleashes its power to energize thousands of homes and businesses with electricity.
Your believer generates the force of life that moves mountains, changes circumstances, and obtains miracles. When your believer is activated by words, this dynamic power is released in the earth on your behalf. This believer is located deep in the heart of man where the issues of life flow.
Proverbs 4:23
23 Keep thy heart with all diligence; for out of it are the issues of life.
What are the issues of life? Using a modern sense of the idea, the issues are everything a person would deal with in life. These issues constitute the attention span of a person's life and every area they face and deal with.
We normally speak of believing for promises from God's Word. This is certainly something you believer is capable of doing. At the same time, deep in your heart, there are things you believe about the issues of life.
Sometimes, these don't line up with the Word of God. When this is discovered you must correct this wrong believing with the Word of God. Otherwise, you keep believing and receiving the wrong thing.