Doing good to others gives comfort to the heart

The first person who benefits from an act of charity is the benefactor himself, by seeing changes in himself and in his manners, by finding peace, by watching a smile form on the lips of another person.

If you find yourself to be in difficulty or distress, show kindness to others, and you will be the first to find solace and comfort. Give to the needy, defend the oppressed, help those in distress, and visit the sick: you will find that happiness surrounds you from all directions.
An act of charity is like perfume it benefits the user, the seller, and the buyer. Furthermore, the psychological benefits that one receives from helping others are indeed great. If you suffer from depression, an act of charity will have a more potent effect on your sickness than will the best available medicine.
Even when you smile upon meeting others, you are giving charity. The Prophet (Blessings and Peace be upon him) said:

“Do not dismiss certain acts of kindness by deeming them to be insignificant, even if (such an act) is to meet your brother with a smiling face (for that is a deed which might weigh heavily in your scale of deeds).”
On the other hand, when you frown upon meeting others, you are displaying a sign of enmity, an act that is so detrimental to brotherhood that only Allah knows the full extent of its evil effects.

The Prophet (pbuh) informed us that the prostitute who once gave a handful of water to a dog was rewarded for that deed with Paradise, which is as wide as the heavens and the earth. This is because the Giver of rewards is Forgiving, Rich, and Worthy of Praise.
O’ you, who are threatened by misery, fear and grief, occupy yourself in the betterment of others. Help others in different way through charity, hospitality, sympathy, and support. And in doing so, you will find all of the happiness that you desire.

We who spends his wealth for increase in self-purification, and has in his mind no.favor from anyone for which a reward is expected in return; except only the desire to seek the Countenance of his Lord, the Most High. He surely will be pleased [when he enters Paradise]. (Qur’an 92: 18-21)