Whose knees came before [death]?
Rashi: My mother's.
Metzudas David: The midwife's. She receives the baby on her knees.
Malbim: My father's.
Why did he say "u'Mah Shadayim"?
Ibn Ezra: This is like Lamah. Similarly, "Mah Yis'onen."
Why did he say "Ki Anik"?
Rashi: It was decreed that I nurse. Because he discusses the day of birth, what is after birth is in future tense.
Devar Eliyahu: He complained about three things - formation ("Lo Sagar Dalsei Vitni"), birth ("Lamah Lo me'Rechem Amus") and living afterwards (nursing). This is like 'Bal Korchacha (against your will) you were formed, Bal Korchacha you were born, and Bal Korchacha you live (Avos 4:22). These are three of the five worlds in which David lived and sang Shirah for them. He was in the womb and sang Shirah. He entered the world and sang Shirah. He looked at (contemplated) his mother's breasts and sang Shirah (Berachos 10a). Each of these three times has a start and end.
