My friends have come to me unsought; the great God gave them to me.

Emerson

The friends thou hast, and their adoption tried,
Grapple them to thy soul with hoops of steel;
But do not dull thy palm with entertainment
Of each new-hatch'd, unfledged comrade.

Shakespeare

He makes no friend who never made a foe.

Tennyson

Who friendship with a knave hath made
Is judg'd a partner in the trade.

Gay

A man's friends are his magnetisms.