The heart can be a sly, sneaky and tricky thing.
WELL, actually, that would be a bit of an understatement. I’m not one to beat around the bushes so I’ll get straight to it.
The heart is a vulnerable fool.
Anyone and everyone will tell you that experiencing a whirlwind of emotions is inevitable, and sometimes drastically unpredictable; like a roller coaster that spins you in all the directions you last expect it will take you and leaves you light-headed and confused at the end. While these emotions can be good for the soul and sources of strength, sometimes they are not and merely steer your thinking from clear rivers into murky ponds of uncertainty.
When the heart is in one specific state, one may easily think it is a permanent or long-term one. If a distressful event happens, one may think they will never swim out of the ocean of sadness it creates- there is so much depth to it, surely the sadness is but a drowning flood that will never end!
Yet how often does God bring ease out of hardship, and the sadness passes? Like a storm that blackened the sky only seconds before a rainbow paints itself.
On the other hand, in a state of elevation or pure delight, we might believe we are forever going to be in this state of gratitude towards God. His blessings on us are accounted for, and we strongly believe nothing can make us forget it… in fact, it’s all we can think about at the moment!
Yet how often does man face calamity and forget all the good he has been given in the blink of an eye?
Such is the heart: it is that which simply flips into a different direction. ‘Heart’ in Arabic is qalb, and qalb means that which turns.
Simply: القَلْبُ: تَحْويلُ الشيءِ عن وجهه
I think the thinking we often have of others – she/he who is heartless, or she/he who has a good heart – are actually highly inaccurate modes of categorizing peoples because the thing is, hearts can change. Hearts DO change. I would hope change for the better of course, but you should never be too confident your currently ‘good’ state is infallible.
This is why in the Quran, the believers are not supposed to settle at the first sign of being guided, but rather, they must seek His help to remain on the path of purification…
… And keep seeking His help, and keep seeking his help, and never ever stop, because to leave yourself to your own devices is the worst thing you could ever do for your heart.
While life spins our minds into mazes and tricks our eyes through illusions, I pray that however the heart fluctuates, that it consistently finds its way back to equilibrium: a state in which the slave of God is always “loving Allah, knowing Him, remembering Him, seeking peace in Him, singling Him out for complete love, fear, hope and dependence– these are qualities that, when combined in a person, constitute a sort of heaven on earth.” 
May He bestow on all of us that steady state for the heart, sakina… a sort of heaven on earth that lives within us, and blossoms out.
And Allah knows best.
 – Don’t Be Sad, Dr. ‘A’id al-Qarni, pg.345