This is one of two verses that falls directly under God's law as "The law of prohibiting and permitting." Within the context, the word [whatsoever] means all things that you take under your possession, be it good or evil. The word itself has a doubled-edged sword reverse effect! It means that once you begin to exercise your authority under this law, you speaking to whatever it is and giving it the command to cease to exist in the earth, in your life or in your situation, heaven has already endorsed it and that you being created in the image and likeness of God is speaking in the earth what was already the mind of God.
You may recall in scripture at one time how Jesus' disciples fell asleep on the boat with His disciples. When the storm came, having lacked the understanding I believe to this law, the disciples panicked! Jesus being God Himself knowing the power of the word, rose up and said to the storm, "Peace, be still!" In that very instant, there was a calm. Under the reverse effect of the law, you permit the things only that are in keeping with the word of God and the mind of God to bless you, to prosper you and to give you the eternal life as promised through Jesus Christ! For just like God, your words have creative power. Watch over it and make it work for you to the glory and honor of the Almighty God.
Be blessed in Jesus name, and continue binding and loosing under your God given authority!