Smiling was the Prophet's Motto
how much important it is in such a world, full of social crises and psychological disease we live in, to keep a smile on our faces like the one the prophet asked his followers to keep all the time.
the prophet released his followers from all heart diseases, psychological crises and life pressures that demolish human life to reach happiness and inner peace. so he made the smile his slogan in sorrows and happiness and was never seen but smiling. his smile cured the sadness of all people around him and healed the pains of his companions.
abdullah bin al hareth reported:" i never saw a man smiling more than the prophet (pbuh)."
but he never went over the limits; he did not exaggerate in the way he smiled or laughed, he used to smile politely and respectfully.
abdullah bin al hareth reported:" the prophet's way to laugh was only by smiling." narrated by al tarmithi
it means that he used to laugh without cackling and full of respect.