Hadith: We used to practice coitus interruptus while the Qur'an was being revealed. Sufyān said: If it had been something unlawful, then the Qur'an would have prohibited us from practicing it

عن جابر بن عبد الله رضي الله عنهما قال: "كنا نعزل والقرآن ينزل". قال سفيان: لو كان شيئا ينهى عنه؛ لنهانا عنه القرآن.
[صحيح] - [متفق عليه]

Jābir ibn ‘Abdullāh (may Allah be pleased with him) reported: We used to practice coitus interruptus while the Qur'an was being revealed. Sufyān said: "If it had been something unlawful, then the Qur'an would have prohibited us from practicing it."
Sahih/Authentic. - [Al-Bukhari and Muslim]

Explanation

Jābir ibn ‘Abdullāh (may Allah be pleased with him) reported that they used to practice coitus interruptus with their wives and female slaves during the lifetime of the Messenger of Allah (may Allah's peace and blessings be upon him) and he approved this method. Had it not been permissible, he would not have approved it. It is as if one claimed that perhaps the Prophet (may Allah's peace and blessings be upon him) did not know what you were doing. Therefore, he said: If the Prophet did not know about this issue, then definitely Allah, Blessed and Exalted, knew about it, and the Qur'an was still being revealed. Had it been something unlawful, Allah would have revealed a verse in the Qur'an prohibiting it. Reconciliation between the texts: The Hadīth of Jābir is evidence that coitus interruptus is permissible, but there are other texts that speak about the impermissibility of such an act. An example of that is the Hadīth that was narrated by Imām Muslim on the authority of Judhāmah bint Wahb who said: I came along with some people to the Messenger of Allah (may Allah's peace and blessings be upon him) and they asked him about coitus interruptus. He said: "That is the disguised form of burying children alive." How can one reconcile between these texts? The answer is: The basic rule is that it is permissible to practice coitus interruptus based on the Hadīth of Jābir and Abu Sa‘īd, may Allah be pleased with them. The Hadīth of Judhāmah, however, applies to the case when coitus interruptus is used as a method of birth control. This could be understood from the Prophet's statement: "That is the disguised form of burying children alive." Another way of reconciliation is to say that coitus interruptus is only disliked, not forbidden.