What is the meaning of "u'Mi Chayai Mishpachas Avi"?
Radak: "U'Mi" applies to both of them. I am not esteemed, that my life is so important. And who is my family 1 [that I should be the king's son-in-law]?! Ralbag - I was a shepherd! And my family comes from Rus ha'Mo'aviyah!
Radak based on Targum Yonasan: [I am not important. The greatness,] that I should be the king's son-in-law, is due to my family, which is esteemed in Yisrael. (Refer to 18:18:1:1*.)
Chomas Anach: David used Chachmah to say ambiguous words to honor Sha'ul, and also David's family. If "u'Mi" applies also to his family, he says that they are not worthy to marry into Sha'ul's family. If it applies only to "my life", he is worthy only due to his family. Yishai taught to 600,000, and was one of four who never sinned!
Was David declining to marry her?
Malbim: No, he was just being humble to say that he is not worthy.
