It is written at the end of the subject about ‘disbeliever’s marriage’ in Durr al-mukhtâr, “If a Muslim girl with nikâh (marriage contract as prescribed by Islam) does not know Islam when she reaches puberty, her nikâh becomes void [she becomes a renegade]. The Attributes of Allâhu ta’âlâ must be told to her, and she must repeat them and say, ‘I believe these. ‘ ” In explaining this, Ibn ‘Âbidîn (rahimah-ullâhu ta’âlâ) said, “If the girl is little, she belongs in her parents’ faith; she is a Muslim.
When she reaches puberty, she does not belong to her parents’ faith any longer. When she reaches puberty, because of her unawareness of Islam, she becomes a renegade. Unless she learns and believes the six tenets of Islam and believes that it is necessary to live up to Islam, she will not continue to be a Muslim even if she utters the Kalimat at-tawhîd, that is, says, ‘Lâ ilâha illa’llah Muhammadun Rasûlullah. ‘ She has to believe the six tenets expressed in ‘Âmantu bi-‘llâhi . . . ,’ and she has to say, ‘I accept the commands and prohibitions of Allâhu ta’âlâ. ‘ “
This explanation of Ibn ‘Âbidîn shows that a disbeliever becomes a Muslim as soon as he says the Kalimat at-tawhîd and believes its meaning. But, like any other Muslim, when he has the chance he has to memorize the following words and learn their meaning precisely: “Âmantu bi’llâhi wa Malâ’ikatihi wa Kutubihi wa Rusûlihi wal-yawm-il-âkhiri wa bil-qadari khairihi wa sharrihi minallâhi ta’âlâ walbâ’thu ba’d-al-mawt haqqun ash-hadu an lâ ilâha illallâh wa ash-hadu anna Muhammadan ‘abduhu wa Rasûluhu.”