Our hearts have been created in a way which makes them dominated by emotion. Sadness is perhaps one of its most powerful states, and the fact that we have so many different words for sadness which all cover different time periods that the heart will be sad, illustrates deeply how soft and sensitive our hearts are.
For example, we know three common words from the Sunnah that describes states of sadness i.e. huzn الحزن, hamm الهم, and ghamm الغم. The difference between them as Ibn al-Qayyim mentioned is that al-huzn refers to a depressed state because of something that happened in the past, al-ghamm is grieving about that which is happening now, and al-hamm is being anxious and worried about something that could happen in the future.
There are no time periods that exist other than the past, present and future. That shows the heart cannot escape being depressed, and we should treat those who are sad with the utmost of love and understanding who need help and support to change to a better state. Yes, it is in the nature of the heart to change, indeed that is why it’s called the Qalb.
Not being able to escape sadness in life doesn’t mean it cannot be treated when it occurs. Just remember though that trying to treat sadness with worldly comforts will always be deficient; true healing only comes from the Qur’an and being able to connect to it at that deeper level which makes you understand that sadness is a natural part of life that will raise you in this life and the next if you view it within its correct context, and not allow it to consume you.
That’s why the Prophet (s) would made du’a for the Qur’an to remove these states. The Qur’an. Anything else will just not cut it. The Qur’an was made to remove sadness, you just need to reflect on it more often, and deeper, for that to happen.