Hadith: During the Prophet's lifetime, a man accused his wife of adultery and disclaimed her child. So the Messenger of Allah (may Allah's peace and blessings be upon him) ordered them both to swear the oath of condemnation against each other, as Allah, the Almighty, instructed, and they did. Then he decided that the child should be with the woman and separated them

عن عبد الله بن عمر رضي الله عنها : أن رجلا اتهم امرأته بالزنا، ونفى كون ولدها منه في زمن رسول الله صلى الله عليه وسلم فأمرهما رسول الله صلى الله عليه وسلم فتلاعنا، كما قال الله تعالى، ثم قضى بالولد للمرأة، وفرق بين المتلاعنين
[صحيح] - [متفق عليه]

‘Abdullāh ibn ‘Umar (may Allah be pleased with him) reported: During the lifetime of the Messenger of Allah (may Allah's peace and blessings be up on him), a man accused his wife of adultery and disclaimed her child. So the Messenger of Allah (may Allah's peace and blessings be upon him) ordered them both to swear the oath of condemnation against each other, as Allah, the Almighty, instructed, and they did. Then he decided that the child should be with the woman and separated them (the man and woman).
[Authentic hadith] - [Narrated by Bukhari & Muslim]

Explanation

In this Hadīth, ‘Abdullāh ibn ‘Umar (may Allah be pleased with him) reports that a man accused his wife of adultery and denied his paternity of her child. She denied his claim and rejected his accusation. So, they swore the oath of condemnation against each other in this way: the husband swore by Allah four times that he is truthful in his accusation, and on the fifth time he invoked the curse of Allah upon himself (if he is a liar). Then the wife swore by Allah four times that he is a liar, and on the fifth time she invoked the anger of Allah upon herself (if he is truthful). After they had condemned one another, the Prophet (may Allah's peace and blessings be upon him) separated them permanently and let the child join the woman and be attributed to her. The child was cut off from the man and no longer attributed to him.