The Prophet (peace be upon him) said: "When you smile to your brother's face, it is charity."
This is an authentic hadîth. It is related in Sunan al-Tirmidhî
(1879) and al-Tirmidhî declared it to be good. It is also related in Sahîh Ibn Hibbân
(475 & 530) and Musnad al-Bazzâr
A man called his friend on the phone thousands of miles away. He said: "So I can be sure of your feelings, I want you to give me smile. And his friend really did smile – a genuine smile from the heart – and the effects of his smile could be heard in his voice while he spoke to his friend overseas. This made the man happy – that someone would smile upon a suggestion, though the other person could not even see him.
There is great wisdom in the Prophet's words: "When you smile to your brother's face is charity."
And indeed, the Prophet (peace be upon him) followed this advice in his everyday life, so much so that `Abd Allah b. al-Hârith said: "I have never seen anyone more in the habit of smiling than Allah's Messenger." [Sunan al-Tirmidhî
Even on the day he died, while lying in his sickbed, he did not neglect to smile. While Abû Bakr was getting the people lined up for prayer, the Prophet managed to stand up and move aside the curtain of his room. His face was like a page from a Qur'an manuscript. Yet he smiled at them, a bright laughing smile. [Sahîh al-Bukhârî
(639) and Sahîh Muslim
The prophet (peace be upon him) saw a smile as a gift of joy – an emotional gift, not a material one – a gift whose substance is received by the heart.
When the Prophet (peace be upon him) said: "your brother's face" he was not implying that smiling is only prescribed upon meeting someone. This advice applies to every occasion where a smile can bring cheer, lighten the mood, or reduce the stress that people are feeling.
Jarîr b. `Abd Allah said: "Since the time I accepted Islam, the Prophet (peace be upon him) never once failed to notice me. Whenever he saw me, he would smile at me." [Sahîh al-Bukhârî
(2809 & 5625) and Sahîh Muslim
It was the Prophet's habit to smile. He even smiled at Fadâlah b. `Umayr – and on that occasion Fadâlah had come with the intention to kill the Prophet (peace be upon him)!
For a smile to be a habitual part of your personality, the facial muscles must be accustomed to smiling. In this way, the hesitancy that we feel when meeting someone, the uncertainty that often comes with interpersonal dealings, will not prevent us from being able to give a broad, heartfelt smile.
There are people who consider frequent smiling to show a deficiency in intelligence or social status. Then there are those who try to smile, but are so unaccustomed to doing so that with great effort they barely manage to curl their lips noticeably. Such people should practice smiling on their own if they must. Maybe they should think of a humorous incident to bring a smile to their face and then share that smile with someone else at no extra cost!
We should not let the differences we might have with people keep us from greeting them with a smile. Likewise, we should not let our possible differences of opinion, or of denomination, or political affiliation, or family background make us stingy with our smiles.
Smiling aids our mental as well as physical health. Indeed, doctor's have begun to incorporate smiling into their therapies. Smiling contributes to lowering blood pressure and improved circulation. It boosts the immune system. It works wherever stress and depression cause harm. Smiling relaxes us and improves our emotional stability.
More than that, a smile is a message about yourself – that your heart is pure and that you are not infected by anxieties, hang-ups, and gloom. A smile is an instant message to those you know as well as those you do not know. It is received and understood even before you speak to or greet someone, and makes that person more receptive to what you have to say.
A genuine smile is charity that you give to yourself. It dispels arrogance from your heart and pessimism from your outlook. It is also charity for others for the happiness and comfort that it brings them. However, the smile has to be real. A mechanical and forced smile will not do the trick.
Smiling is something we want to be contagious. We want it to spread amity and friendship among the people. We want it to make people think better of one another, to trust each other, and learn to get along, whatever their other differences might be. Smiling, it can be hoped, will help to establish the value of good conduct among all human beings.