A longstanding source of embarrassment for Muslims has been the account of Muhammad's marriage to Zaynab bint-Jahsh, the ex-wife of his own adopted son, Zaid.
The first place we will go to get some context on the affair is The History of al-Tabari (915 AD), which was written by the same author that produced the most important Tafsir (Quranic commentary) in Islam:
The History of al-Tabari, Vol 8, pg. 2-3
The Messenger of God came to the house of Zayd b. Harithah. (Zayd was always called Zayd b. Muhammad) Perhaps the Messenger of God missed him at that moment, so as to ask, "Where is Zayd?" He came to his residence to look for him but did not find him. Zaynab bt. Jalish, Zayd's wife, rose to meet him. Because she was dressed only in a shift, the Messenger of God turned away from her. She said: "He is not here, Messenger of God. Come in, you who are as dear to me as my father and mother!" The Messenger of God refused to enter.
Zaynab had dressed in haste when she was told "the Messenger of God is at the door." She jumped up in haste and excited the admiration of the Messenger of God, so that he turned away murmuring something that could scarcely be understood. However, he did say overtly: "Glory be to God the Almighty! Glory be to God, who causes hearts to turn!"
When Zayd came home, his wife told him that the Messenger of God had come to his house. Zayd said, "Why didn't you ask him to come in?" She replied, "I asked him, but he refused." "Did you hear him say anything?" he asked. She replied, "As he turned away, I heard him say: "Glory be to God the Almighty! Glory be to God, who causes hearts to turn!""
So Zayd left, and, having come to the Messenger of God, he said: "Messenger of God, I have heard that you came to my house. Why didn't you go in, you who are as dear to me as my father and mother? Messenger of God, perhaps Zaynab has excited your admiration, and so I will separate myself from her." The Messenger of God said, "Keep your wife to yourself." Zayd could find no possible way to [approach] her after that day. He would come to the Messenger of God and tell him so, but the Messenger of God would say to him, "Keep your wife." Zayd separated from her and left her, and she became free.
While the Messenger of God was talking with Aishah, a fainting overcame him. When he was released from it, he smiled and said, "Who will go to Zaynab to tell her the good news, saying that God has married her to me?" Then the Messenger of God recited: "And when you said unto him on whom God has conferred favor and you have conferred favor, 'Keep your wife to yourself ...' and the entire passage. According to Aishah, who said: "I became very uneasy because of what we heard about her beauty and another thing, the greatest and loftiest of matters-what God had done for her by giving her in marriage. I said that she would boast of it over us."
In the above account, we see that:
Eventually, Zaid divorces Zaynab, as a direct result of Muhammad's encounter with her. Afterwards, once Zaynab's waiting period (Iddah) was over, Muhammad told Zaid to mention him to Zaynab, before going to her house himself:
Sahih Muslim 1428b
Anas (Allah be pleased with him) reported:
When the 'Iddah of Zainab was over, Allah's Messenger (ﷺ) said to Zaid to make a mention to her about him. Zaid went on until he came to her and she was fermenting her flour. He (Zaid) said: As I saw her I felt in my heart an idea of her greatness so much so that I could not see towards her (simply for the fact) that Allah's Messenger (ﷺ) had made a mention of her. So I turned my back towards her. and I turned upon my heels, and said: Zainab, Allah's Messenger (ﷺ) has sent (me) with a message to you. She said: I do not do anything until I solicit the will of my Lord. So she stood at her place of worship and the (verse of) the Qur'an (pertaining to her marriage) were revealed, and Allah's Messenger (ﷺ) came to her without permission.
The above narration mentions verses of the Quran being revealed after Muhammad showed interest in Zaynab. Those verses are:
Surah 33:4
4 Allah does not place two hearts in any person's chest. Nor does He regard your wives as ˹unlawful for you like˺ your real mothers, ˹even˺ if you say they are. Nor does He regard your adopted children as your real children. These are only your baseless assertions. But Allah declares the truth, and He ˹alone˺ guides to the ˹Right˺ Way.
Surah 33:37-40
37 And ˹remember, O Prophet,˺ when you said to the one for whom Allah has done a favour and you ˹too˺ have done a favour, "Keep your wife and fear Allah," while concealing within yourself what Allah was going to reveal. And ˹so˺ you were considering the people, whereas Allah was more worthy of your consideration. So when Zaid totally lost interest in ˹keeping˺ his wife, We gave her to you in marriage, so that there would be no blame on the believers for marrying the ex-wives of their adopted sons after their divorce. And Allah's command is totally binding.
38 There is no blame on the Prophet for doing what Allah has ordained for him. That has been the way of Allah with those ˹prophets˺ who had gone before. And Allah's command has been firmly decreed.
39 ˹That is His way with˺ those ˹prophets˺ who deliver the messages of Allah, and consider Him, and none but Allah. And sufficient is Allah as a ˹vigilant˺ Reckoner.
40 Muhammad is not the father of any of your men, but is the Messenger of Allah and the seal of the prophets. And Allah has ˹perfect˺ knowledge of all things.
The above passages complete the picture in a few important ways:
Notice also that Muhammad's justification for this whole situation is so that Allah would demonstrate "that there would be no blame on the believers for marrying the ex-wives of their adopted sons after their divorce". Not only does this reek of an ad-hoc justification for lust, and for what must've been an exceptionally rare scenario, it is now a scenario that is impossible to ever occur again, because Muhammad has abolished adoption. Therefore, there are no more "adopted sons" whose ex-wives can be remarried, and so the entire purpose of the affair has been annulled.
After the marriage took place, Aisha's fears about Zaynab, as mentioned in al-Tabari, were confirmed, as we read:
Sahih al-Bukhari 7420 (also 7421)
Narrated Anas:
Zaid bin Haritha came to the Prophet (ﷺ) complaining about his wife. The Prophet (ﷺ) kept on saying (to him), "Be afraid of Allah and keep your wife." Aisha said, "If Allah's Messenger (ﷺ) were to conceal anything (of the Qur'an he would have concealed this Verse." Zainab used to boast before the wives of the Prophet (ﷺ) and used to say, "You were given in marriage by your families, while I was married (to the Prophet) by Allah from over seven Heavens." And Thabit recited, "The Verse:-- 'But (O Muhammad) you did hide in your heart that which Allah was about to make manifest, you did fear the people,' (33.37) was revealed in connection with Zainab and Zaid bin Haritha."
From the above, we can see that Zaynab clearly saw marriage to Muhammad as moving up in the world, and that would reasonably have contributed to her relationship with Zaid souring. From everything we've looked at so far, every indication is that both Zaid and Zaynab knew exactly what Muhammad wanted to happen, and this directly caused their divorce.
The same Bible which Muhammad constantly claimed to affirm (Surah 3:3-4, 5:43-48, 5:68, etc.) has much to say that relates to this whole ordeal.
In the first place, we have Muhammad saying "Glory be to God the Almighty! Glory be to God, who causes hearts to turn!", about a situation that demands either the death of Zaid, or divorce, when the Bible makes it clear that God hates any and all divorce:
Malachi 2:16
16 For the LORD, the God of Israel, saith that he hateth putting away: for one covereth violence with his garment, saith the LORD of hosts: therefore take heed to your spirit, that ye deal not treacherously.
Yet, in the spite of the above, Muhammad tells us in the Quran that God wanted this divorce, to show that what Muhammad did was okay.
Even apart from the divorce itself, the Lord also taught that Muhammad's marriage to Zaynab was adultery (Matthew 19:9, Mark 10:11-12, Luke 16:18):
Matthew 5:32
32 But I say unto you, That whosoever shall put away his wife, saving for the cause of fornication, causeth her to commit adultery: and whosoever shall marry her that is divorced committeth adultery.
The above shows that Zaid and Zaynab's divorce was unjustified, and therefore sinful, and also that Muhammad's remarriage of the divorced Zaynab was sinful - both enabling the major sin of adultery. But Muhammad "affirmed the Bible" - a Bible which never existed, and completely contradicts the only "Bible" that history has ever known or corroborated.
Not only did Muhammad cause the divorce of his adopted son with his lust, and commit adultery, he then abolished one of humanity's most merciful institutions, adoption, to justify his sin.
He praised God for divorce and adultery, and took advantage of a woman seeing her opportunity to move up in the world, and his adopted son's seeing the writing on the wall, to disinherit his son, and take yet another woman to himself, all the while blasphemously declaring this to be "the will of God", because "God" is actually Muhammad. This account demonstrates that fact so clearly, that one would have to be wicked, or spiritually blinded to miss it.