Is equality among wives mandatory regarding sexual intercourse (jima')?

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There is a difference of scholarly opinion regarding whether equality must be observed between wives in intercourse, which is the position of Malik and Shafi'i. This is because intercourse is related to desire and inclination, and there is no means to equalize these internal feelings, as the heart may incline to one over the other, referencing Quran 4:129, 'And you will never be able to be just between wives, even if you should strive eagerly.' However, if equalization in intercourse is possible, it is better and preferable as it achieves greater justice. The Prophet (PBUH) used to divide his time justly and then supplicate, 'O Allah, this is my division concerning what I control, so do not blame me concerning what I do not control.' It is also reported that he used to equalize even in foreplay.