In the Anguttara Nikaya 7.35, the Buddha said this
“He gives what is beautiful, hard to give, does what is hard to do, endures painful, ill-spoken words.
His secrets he tells you, your secrets he keeps.
When misfortunes strike, he doesn’t abandon you; when you’re down & out, doesn’t look down on you.
A person in whom these traits are found, is a friend to be cultivated by anyone wanting a friend.” http://www.accesstoinsight.org/tipitaka/an/an07/an07.035.than.html
If one wants to have many friends, one should be a friend to many. And one should have qualities of a friend worth associating with!
