“A merry heart maketh a cheerful countenance: but by sorrow of the heart the spirit is broken.” – Proverbs 15:13 KJV

“A merry heart doeth good like a medicine: but a broken spirit drieth the bones.” – Proverbs 17:22 KJV

It has been said that laughter is the best medicine. Most often we do not see this as true. And for some of us that believe it is true, we loose sight of this and allow stress and pressure to squeeze life and health out of us.
Everything in life starts from the heart. Good or bad: success, failure, promotion, demotion, joy, sadness, everything starts from the heart!
Life is home in the heart. The heart is the gateway of life into the being. All that the being or person will be comes from either of the two kingdoms of the spirit: Light and Darkness, through the heart.

In the true sense of it, man CANNOT CREATE, he RECREATES! Nothing is new under the Sun. Whatever is, has been in the spirit realm, created by forces other than man. Man is only a vehicle through which these forces display or express their creations: good or bad; whether it be science or art, in all their forms.

“Fear, and the pit, and the snare, are upon thee, O inhabitant of the earth. And it shall come to pass, that he who fleeth from the noise of the fear shall fall into the pit; and he that cometh up out of the midst of the pit shall be taken in the snare: for the windows from on high are open, and the foundations of the earth do shake.” (Isaiah 24:17-18).

The windows from on high are open! Imaginations and thoughts come to us from these; from the air and we, like antennas, catch these and “produce” them. Man is under the influence of powers greater than him! That is the source of breakthroughs in science, technology, and all art forms, which includes music!
What you obey, rules or influences you! Good or bad!

“Know ye not, that to whom ye yield yourselves servants in obedience, his servants ye are whom ye obey; whether of sin to death, or of obedience to righteousness?” (Romans 6:16).   

That is why we are advised to watch what things we allow to enter our hearts.

“Keep thy heart with all diligence; for out of it are the issues of life.” (Proverbs 4:23).

Every issue of your life proceed from your heart!
Ugly and wicked thoughts come to you through your heart, to steal, kill or destroy your inner beauty and rob you of your testimony! As they come into your heart, they should be pulled down instantly or caged, stifled and not allowed to have life.

“Casting down imaginations, and every high thing that exalteth itself against the knowledge of God, and bringing into captivity every thought to the obedience of Christ;” (2 Corinthians 10:5).

God wants you to “rejoice always”.

Sadness, worry and melancholy are not of God and so should be pulled down!
When projections come from the depths of evil to make you sad, worry or melancholic, through things you see, hear, smell, touch or feel, don’t give a foot-hold to the devil! Render his projections null and void!
There are many programmes in the air-wave. You choose what you desire. Both sadness and joy are in the spiritual air-wave, choose to be happy! Its your choice!
Sadness is a property of the devil. He tries selling it to you so that through it he would have entry into your life and afflict you!
Being under the control of your subconscious mind, all organs of your body respond to the thoughts and imaginations of your heart; and reproduce what you have programmed there.
Deliberately refuse the devil’s item: sadness. Choose to rejoice, which is the Lord’s. As you retain this knowledge of God (Romans 1:28), His good plans for you in your heart, it becomes a “programme”, which runs or directs every fiber and organ of your being!
The health of your body organs and system, are determined by the programme embedded in your subconscious. This in turn reflects in your physical health!

Resisting the devil simply means refusing to write his “programme” into your subconscious mind.
When you choose God’s plan, rejoicing, no matter what comes your way, that is a powerful weapon that would make the devil angry and flee, even if it is for a season! 
Hey, be happy!