In Buddhism, spreading loving kindness is the power of the mind, because it makes the mind bright and without murkiness.
If a human being spreads his loving kindness with his bright heart, with his pure heart, his loving kindness is full of power and virtue which can make all sentient beings live happily without exploiting each other, even elephants, tigers, snakes and various animals can happily live together. If the heart of a human being consists of loving kindness, brightness and purity, this heart has enough power to make all sentient beings happy and peaceful.
Thus, loving kindness is the pole which supports this world and makes the world happy, a world that is without anger, hatred, envy, revenge or vindication. When a person has good conduct and moral practice he also has loving kindness for himself. This loving kindness will make him love and have mercy to all others as well.
So this loving kindness is the great power which spreads limitlessly, to himself, friends, kinsmen, enemies, people throughout all the countries, all sentient beings in the three worlds and even to all beings who are in suffering, with the thought of good will that all may be happy, escape from all dangers and find more and more happiness.
The pure and bright loving kindness which spreads from ones heart as mentioned above can be very powerfull and is regarded as the most important virtue which must be applied and developed all the time.
Before one likes to spread ones loving kindness to others one must indeed make up ones mind to be brightly illuminated and pure. This kind of loving kindness can only support the world.