Rashi: Hashem made [one couple] initially - Adam and Chavah.

Rashi citing Agadah: Those who married Nochriyos gathered to the Navi, and told him 'did Avraham not do so? He married Hagar in addition to his wife!'

Radak: Avraham, who was one and a father to all who came after him, he did not do like you do. He did not pursue lust!

Radak citing Targum Yonasan: Avraham was alone...

Malbim: He proves their sin from the creation of man. When Hashem created man, he did not make them male and female separate, like other living beings. Initially Adam was created alone, and Chavah was one of his Tzela'os. She was initially one body with him. Hashem made him with She'aro (his wife).

Rashi: All other Ruchos and Nefashos came from Adam.

Rashi citing Agadah: The Navi answered them, Avraham did not intend like you ¹ . He did not put his eyes on Hagar; he had a different intent.

Radak: Avraham had extra Ru'ach, therefore he did not pursue lust, and had Bi'ah only for the sake of Peru u'Rvu.

Radak citing his father: Avraham did like us - he abandoned his wife, and had Bi'ah with his Shifchah Hagar, even though he had extra Ru'ach and was a Navi! She'ar is extra and an attribute, like "Yeser Seis v'Yeser Az" (Bereishis 49:3). Just like Yeser can mean She'ar, attribute and praise, She'ar can mean She'ar, excess and attribute. I.e. Avraham had extra Ru'ach and attributes.

Malbim: Adam and his wife were created together, with one Ru'ach. Other living beings were created as two, both in body and Ru'ach. Why did He do so? This shows that man's Zivug must resemble him and unite with him, both in flesh (be from his nation and Beis Avosav) and Ru'ach (they have one creed and Emunah) - "ha'Lo Av Echad l'Chulanu Kel Echad Bera'anu" (10).

Rashi, based on Targum Yonasan: One of them seeks pretexts against his wife, who is Zera Elokim ¹ . What is this abomination, that he disgraces her!?

Rashi citing Agadah: They asked the Navi, what was Avraham's intent?

Malbim: What do we learn from that unity that must be in the couple (from their initial creation as one)?

Rashi citing Agadah: The Navi answered, he wanted to have Zera Elokim.

Radak: Avraham had Bi'ah even with Sarah only in order to leave over Zera Elokim - Hashem commanded him Peru u'Rvu.

Radak citing his father: The Navi answered, Avraham had Bi'ah with Hagar only because he wanted seed; he had no children from his wife Sarah. Even so, he did not betray Sarah - he did so with her desire and permission.

Malbim: The Navi answers, via the unity in the couple in flesh and Ru'ach, the seed born will be Zera Elokim - not Zera Kil'ayim Sha'atnez, like that of animals that do not guard lineage and unity. Rather, it will be like Zera of Adam, who begat "bi'Dmusu", "b'Tzalmo b'Tzelem Elokim" (Bereishis 5:3, 1:27).

Rashi: Your Ru'ach should not betray the wife of your youth.

Radak: Not one of you should betray the wife of your youth, to abandon her and have Bi'ah with Bas El Nechar.

Malbim: Guard the Ru'ach of lust.

Malbim: Do not hate her, and love another in place of her, for the intent of the creation was that both have one Ru'ach, of love and desire.