1)
Why did Shlomo mention that Hashem gave to him serenity?
1.
Radak: This is why I can build it - "v'Heni'ach Lachem mi'Kol Oyveichem; v'Hayah ha'Makom Asher Yivchar Hashem; "l'Shichno Sidreshu" (Devarim 12:10-11, 5).
2)
Why did he say "Ein Satan v'Ein Pega Ra"?
1.
Malbim: I do not have conflict from nearby nations, and enemies from afar do not chance to strike me.
