God gave the seventh commandment, "You shall not commit adultery" (Exodus 20:14; Deuteronomy 5:18), to protect the honor and sanctity of marriage. It is through marriage and the family that we learn how to conduct proper relationships, both with other people and with God. Since it is such an important institution to character development, God does not tolerate its defilement.
Did Mohammad (PBUH) commit adultery? Is the sky blue? Rather than commenting on Mohammad's (PBUH) licentious behaviour, I will give you a list of some of his transgressions, and let you decide for yourselves...
Qur'an 33:51 - "You may have whomever you desire; there is no blame."
Tabari VIII:187: "The [sixty-two-year old] Messenger of Allah married Mulaykah. She was young and beautiful. One of the Prophet's wives came to her and said, 'Are you not ashamed to marry a man who killed your father during the day he conquered Mecca?" She therefore took refuge from him."
Qur'an 66:1 "O Prophet! Why forbid yourself that which Allah has made lawful to you? You seek to please your consorts."
Qur'an 66:5 "Maybe, if he divorces you (all), Allah will give him in exchange consorts better than you - submissive, faithful, obedient, adorers who worship, who travel, and are inclined to fasting - previously married or virgins."
Tabari VIII:117: "Dihyah had asked the Messenger for Safiyah when the Prophet chose her for himself. Muhammad gave Dihyah her two cousins instead." Ishaq:511 "When he protested, wanting to keep Safiyah for himself, the Apostle traded for Safiyah by giving Dihyah her two cousins. The women of Khaybar were distributed among the Muslims."
Bukhari:V5B59N524 "The Muslims said among themselves, 'Will Safiyah be one of the Prophet's wives or just a lady captive and one of his possessions?'"
Tabari VIII:110 "When Abu Sufyan learned that the Prophet had taken her, he said, 'That stallion's nose is not to be restrained!'"
Bukhari:V4B52N143V5B59N523 "When we reached Khaybar, Muhammad said that Allah had enabled him to conquer them. It was then that the beauty of Safiyah was described to him. Her husband had been killed [by Muhammad], so Allah's Apostle selected her for himself. He took her along with him till we reached a place where her menses were over and he took her for his wife, consummating his marriage to her, and forcing her to wear the veil.'"
Tabari VIII:122Ishaq:515: "Muhammad commanded that Safiyah should be kept behind him and he threw his cloak over her. Thus the Muslims knew that he had chosen her for himself."
Ishaq:517 "When the Apostle took Safiyah on his way out of town, she was beautified and combed, putting her in a fitting state for the Messenger. The Apostle passed the night with her in his tent. Abu Ayyub, girt with his sword, guarded the Apostle, going round the tent until he saw him emerge in the morning. Abu said, 'I was afraid for you with this woman for you have killed her father, her husband, and her people."
Tabari IX:126: "The Messenger of Allah married fifteen women. He combined eleven at a time and left behind nine."
Ishaq:311: "The Apostle saw Ummu'l when she was a baby crawling before his feet and said, 'If she grows up, I will marry her.' But he died before he was able to do so."
Bukhari:V9B87N139-40: "Allah's Apostle told Aisha, 'You were shown to me twice in my dreams [a.k.a. sexual fantasies]. I beheld a man or angel carrying you in a silken cloth. He said to me, "She is yours, so uncover her." And behold, it was you. I would then say to myself, "If this is from Allah, then it must happen."'"
Tabari IX:133: "Juwayriyyah was chosen by the Messenger for himself on the day of the Muraysi raid from the captives." "Muhammad married Umm, who had embraced Christianity."
Tabari IX:134: "Muhammad took Zaynab [his daughter-in-law] but Allah did not find any fault in the [incestuous] relationship and ordered the marriage." (See comment
Tabari IX:135: "When the Prophet scrutinized the captives on the day of Khaybar, he threw his cloak over Safayah. Thus she was his chosen one." Tabari IX:139 "The Messenger married Ghaziyyah after the news of her beauty and skill had reached him."
Tabari IX:137"Allah granted Rayhanah of the [Jewish] Qurayza to His Messenger as booty [but only after she had been forced to watch him decapitate her father and brother, seen her mother hauled off to be raped, and her sisters sold into slavery]."
Tabari IX:137"Mariyah, a Copt slave, was presented to the Prophet. She was given to him by Muqawqis, the ruler of Alexandria."
Tabari IX:138 "The Prophet married Aliyyah, a Bakr woman. He gave her gifts for divorce and left her. He also married Qutaylah, but he died before he could consummate the marriage."
Tabari IX:139"Layla approached the Prophet while his back was to the sun and clapped him on his shoulder. He asked her who it was and she replied, 'I am the daughter of one who competes with the wind. I am Layla. I have come to offer myself to you.' He replied, 'I accept.'" [Layla shared her story with her parents.] "They said, 'What a bad thing you have done! You are a self-respecting girl, but the Prophet is a womanizer.'"
Tabari IX:147 "A eunuch named Mubur was presented to Muhammad along with two slave girls. One he took as a concubine, the other he gave to Haasn."
Ishaq:186"He took me into Paradise and there I saw a damsel with dark red lips. I asked her to whom she belonged, for she pleased me much when I saw her."
"The Messenger sent Hatib to Muqawqis, the ruler of Alexandria. Hatib delivered the letter of the Prophet, and Muqawqis gave Allah's Apostle four slave girls."
The Basis for why Mohammad (PBUH) Forbid adoption where he took his adopted son's wife:
"In this year the Messenger married Zaynab bt. Jahsh [a first cousin: Allah's Messenger came to the house of Zayd bin [son of] Muhammad. Perhaps the Messenger missed him at that moment. Zaynab, Zayd's wife, rose to meet him. She was dressed only in a shift.... She jumped up eagerly and excited the admiration of Allah's Messenger, so that he turned away murmuring something that could scarcely be understood. However, he did say overtly, 'Glory be to Allah Almighty, who causes hearts to turn!' So Zayd went to Muhammad. 'Prophet, I have heard that you came to my house. Why didn't you go in? [Dad,] Perhaps Zaynab has excited your admiration, so I will leave her.'"
"One day Muhammad went out looking for Zayd. Now there was a covering of haircloth over the doorway, but the wind had lifted the covering so that the doorway was uncovered. Zaynab was in her chamber, undressed, and admiration for her entered the heart of the Prophet. After that Allah made her unattractive to Zayd.'"
"Zayd left her, and she became free. While the Messenger of Allah was talking with Aisha, 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? Allah has married her to me.' Then the Prophet recited [Qur'an 33] to the end of the passage. Aisha said, 'I became very uneasy because of what we heard about her beauty and another thing, the loftiest of matters, what Allah had done for her by personally giving her to him in marriage. I said that she would boast of it over us.'"
The resulting Quran Surah:
"Allah has not made your wives whom you divorce your mothers: nor has He made your adopted sons your sons. Such is (only) your (manner of) speech by your mouths."
"The Prophet has a greater claim on the faithful than they have on themselves, and his wives are their mothers.... This is written in the Book."
"You hid in your mind and your heart that which Allah was about to manifest: you feared the people, but it is more fitting that thou shouldst fear Allah. Then when Zayd had dissolved (his marriage) with her, with the necessary (formality), We gave her to you, joining her in marriage to you: in order that there may be no difficulty or sin for the Believers in the wives of their adopted sons, when the latter have dissolved with the necessary (formality) (their marriage) with them. And Allah's command must be fulfilled."
"O Prophet! We have made lawful to you all the wives to whom you have paid dowers; and those whom your hands possess out of the prisoners of war spoils whom Allah has assigned to you; and daughters of your paternal uncles and aunts, and daughters of your uncles and aunts, who migrated with you; and any believing woman if the Prophet wishes her; this is a privilege for you only, and not for the rest of the Believers; We know what We have appointed for them as to their wives and the captives whom they possess; in order that there should be no difficulty for you and that you should be free from blame."
"You may put off whom you please, and you may take to you whomever you desire. You may defer any of them you please, and you may have whomever you desire; there is no blame on you if you invite one who you had set aside. It is no sin."
"O Prophet, say to your wives and consorts: 'If you desire this world's life and its glittering adornment, then come! I will provide them for your enjoyment and set you free in a handsome manner. And if you desire Allah and His Messenger and the latter abode, then lo! Allah hath prepared for the good-doers an immense reward."
"O Consorts of the Prophet! If any of you are guilty of unseemly conduct, shamelessness, or lewdness, the punishment will be doubled, and that is easy for Allah. But any of you that is devout, obedient, and submissive in the service to Allah and His Messenger, and does good, to her shall We grant her reward twice. We have prepared for her a generously rich provision."
"Consorts of the Prophet! You are not like any of the (other) women. Fear and keep your duty, lest one in whose heart is a disease should be moved with desire. Stay quietly in your apartment. Make not a dazzling display like that of the former times of Ignorance. Perform the devotion, pay the zakat; and obey Allah and His Messenger. And Allah wishes to cleanse you with a thorough cleansing. And bear in mind that which is recited in your houses of the revelations of Allah and the wisdom."
"It is not fitting for a Muslim man or woman to have any choice in their affairs when a matter has been decided for them by Allah and His Messenger. They have no option. If any one disobeys Allah and His Messenger, he is indeed on a wrong Path."
"Prohibited to you are: your mothers, daughters, sisters.... Also (prohibited are) women already married, except slaves who are captives."
"I entered the Mosque, saw Abu, sat beside him and asked about sex. Abu Said said, 'We went out with Allah's Apostle and we received female slaves from among the captives. We desired women and we loved to do coitus interruptus.'"