Sayyiduna Abu Musa Ash'ari (may Allah be pleased with him) narrates: The Noble Prophet (peace and blessings be upon him) said: "The example of a good companion is like that of a perfume seller; even if you do not buy anything from him, his fragrance will still reach you. And the example of a bad companion is like that of a blacksmith; even if he does not burn you with his sparks, his foul smell will still reach you."