1)
What is the meaning of "Yarad b'Yado"?
1.
Radak, Targum Yonasan: It is as if says Horid [b'Yado].
2.
Radak, Malbim: By chance, it descended [by itself] to his hand. He did not take it intentionally. When he took his Kelim, he did not pay attention to what he takes and what he leaves, like one who flees. Hashem arranged that it was among what he took. Therefore it says Yarad, and not Horid.
2)
Why does it mention that he took the Efod?
1.
Malbim: This is so we will know how the Urim v'Tumim came to David. It came in order that he would save Ke'ilah.
