We used to practise 'azl while the Quran was revealed (during the days when the Prophet was alive).
Sahih Muslim Book 16, Hadith 161
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Sahih Muslim Book 16, Hadith 160 Next Hadith → We used to practise 'azl during the life of Allah's Messenger (ﷺ).

Sahih Muslim Book 16, Hadith 162