From a Buddhist sutra:
Once the Blessed One told His monks the following story:
'There was once a pair of jugglers who did their acrobatic feats on a bamboo pole. One day the master said to his apprentice: 'Now get on my shoulders and climb up the bamboo pole.' When the apprentice had done so, the master said: 'Now protect me well and I shall protect you. By watching each other in that way, we shall be able to show our skill, we shall make a good profit and you can get down safely from the bamboo pole.' But the apprentice said: 'Not so, master. You! O Master, should protect yourself, and I too shall protect myself. Thus self-protected and
self-guarded we shall safely do our feats.'
'This is the right way,' said the Blessed One and spoke further as follows:
'It is just as the apprentice said: 'I shall protect myself,' in that way the Foundation of Mindfulness should be practised. 'I shall protect others,' in that way the Foundation of Mindfulness should be practised. Protecting oneself one protects others; protecting others one protects oneself.
'And how does one, in protecting oneself, protect others? By the repeated and frequent practice of meditation.
'And how does one, by protecting others, protect oneself? By patience and forbearance, by a non-violent and harmless life, by loving kindness
and compassion.' (Satipatthana, Samyutta, No:19)