1)
What should the Goyim hear?
1.
Radak: That I warn you.
2.
Malbim: Hashem appointed you to afflict Yisrael.
2)
What is the meaning of "u'De'i Edah""?
1.
Radak: The Edah of Yisrael should know.
2.
Malbim: Know the warning that I gave to them.
3)
What is the meaning of "Es Asher Bam"?
1.
Rashi: The evil in their hands.
2.
Radak, based on Targum Yonasan: See your sin - the sins in your people, from small to big.
3.
Malbim: What I testified against them. Know that I do not strike them for naught - I warned them first!