Ibn ‘Abbās (may Allah be pleased with him) reported that the Prophet (may Allah's peace and blessings be upon him) said: ''A previously-married woman is more entitled to give a decision about her marriage than her guardian, whereas a virgin's permission is to be sought. Her permission is her silence.''
This Hadīth indicates that a previously-married woman is worthier than her guardian of giving herself in marriage. This means that her guardian should not marry her off until she permits him by expressing her will, because she is worthier than him of approving the contract. If she does not agree, her guardian will have no say. However, a virgin who is of age should be approached for her permission. Her silence suffices as her permission. Yet, she must not be forced to get married.