1)
Why will they bow to him?
1.
Malbim: It is because they recognize his Chachmah and attributes. Also this is a reward for doing Mishpat!
2)
Do we find that all Goyim will serve him?
1.
Rashi: "V'Chol ha'Aretz Mevakshim Es Pnei Shlomo...; v'Hemah Mevi'im Ish Minchaso (Melachim I, 10:24-25).
2.
Malbim: They will want to serve him due to recognizing his Chachmah and attributes (Melachim I, 5:10).
