1)
Why does the verse repeatedly mention kneeling and falling?
1.
Yevamos 103a: The seven expressions ("Kara Nafal Shachav... Kara Nafal... Kara... Nafal" teach that he had seven acts of Bi'ah with her. 1
2.
Radak: Often, matters are repeated to strengthen them. He kneeled and did not straighten - "Sham Nafal Shadud."
1
Radak: This is difficult. The Drashah I brought above on ba'Shemichah (refer to 4:18:1:4) contradicts this. (There is no contradiction according to Maharzu (refer to 4:18:1:4 2
), nor according to the other Drashos of ba'Shemichah (refer to 4:18:1:1-3). According to Radak, why did he kneel and lie between her legs?! - PF)