The key to happiness is in  
understanding and worshipping God.

 This worship serves as a reminder of Him and keeps us always conscious of Him and hence  we stay away from evil, committing injustices and oppression.
 It elevates us to being righteous and of good character.

 By following His commands, we lead a life that guides us to the best in all our affairs. When we lead such a meaningful life, then and only then  
are we able to see happiness all around us, at any given moment  
and even on the darkest of times. 

The nature of the human condition means that amongst great  
sorrow can be moments of joy and sometimes in moments of  
despair we can find an anchor in the things that bring us happiness. 
Prophet Muhammad said, “Indeed amazing are the affairs of a  
believer! They are all for his benefit. If he is granted ease then  
he is thankful, and this is good for him. And if he is afflicted  
with a hardship, he perseveres, and this is good for him.”