With some contemplation we see that the existence of the entire human race is dependant on giving and kindness. For every person has various moments when he needs the assistance of others. At one point a person might need financial help in the form of a loan. This is also true of wealthy people who sometimes need a loan. Or, one might need that his fellow give him work so he can make a living. At other times a person might need not financial but “human” assistance, such as at a time of celebration—people need other people to share joy, for no person can enjoy complete happiness when he is by himself. Similarly, when a person is sad, he needs friends for consolation and comfort. This is the mitzvah of consoling the mourning.
At times a person might be on the road, transporting a heavy load and he needs help adjusting it. This is the mitzvah of perika (unloading) and te’eenah (loading). And if he should be forced to lodge at other people’s homes, he needs to be accepted with dignity and respect. This is the mitzvah of hachnasas orchim (hospitality).
If he should become ill, he needs other people to visit him and assist him as necessary. This is the mitzvah of bikur cholim (visiting the sick). And when one’s days are over and he passes away, he needs people who will do true loving-kindness for him.
In short, the world cannot exist without this trait of kindness, and that is why the Torah focuses so often on this mitzvah.