and it is well-known, and it perfectly applies to what is known today as "installment sale," so what is its ruling? The scholars have differed on this matter, both in the past and present, into three opinions: The first is that it is absolutely invalid. This is the view of Ibn Ḥazm. The second is that it is not permissible unless they separate on one of them. Similarly, if only the installment price is mentioned. The third is that it is not permissible, but if it occurs and the lower of the two prices is paid, it is permissible. 1 - The evidence for this view is the apparent prohibition in the previously mentioned ḥadīths, as the original ruling implies invalidity. This is closer to being correct if not for what will be mentioned when discussing the evidence for the third opinion. 2 - These scholars have argued that the prohibition is due to the ignorance of the price. Al-Khaṭṭābī said: "If the price is unknown, the sale is invalid. But if it is settled on one of the two matters in the session of the contract, it is valid." And I say: Their reasoning for prohibiting two sales in one sale due to ignorance of the price is rejected because it is merely an opinion opposed to the explicit text in the ḥadīth of Abū Hurayrah and Ibn Masʿūd that it is usury. This is from one perspective. From another perspective, this reasoning is based on the claim that offer and acceptance are obligatory in sales, which has no evidence in the Book of Allāh and the Sunnah of the Messenger of Allāh (ṣallá Allāhu ʿalayhi wa-sallam). Rather, mutual consent and good will suffice, and whatever indicates and expresses them is the legitimate sale, which is known to some as "sale by mutual consent." Al-Shawkānī said in "al-Sayl al-Jarrār" (3/126): "And this mutual consent that achieves mutual satisfaction and good will is the legitimate sale that Allāh has permitted, and any addition to it is imposing what the sharīʿah has not imposed." Shaykh al-Islām explained this in "al-Fatāwá" (29/5-21) in a manner that leaves nothing further to be added