What inspired Shlomo to say this now?
'Rashi': Since he saw a cloud, he knew that the Shechinah is there. It normally dwells in Arafel - "u'Moshe Nigash El ha'Arafel Asher Sham ha'Elokim" (Shemos 20:18). Surely He wants to stay here!
'Rashi' (from Mechilta Bo 12): He saw the cloud, which showed that the Shechinah dwells in the house that he built ? "Ki be'Anan Era'eh Al ha'Kapores" (Vayikra 16:2).
Where did Hashem say that He will dwell in Arafel?
Radak: He said that He will dwell among Yisrael in Arafel, i.e. a cloud ? "v'Shachanti b'Soch Bnei Yisrael" (Shemos 29:48).
Radak (from Mechilta Bo 12): Chazal expounded "Ki be'Anan Era'eh Al ha'Kapores" (Vayikra 16:2) to refer to the smoke of the Ketores, but the simple meaning is His cloud of glory. His honor was constantly seen in the Mishkan ? "Chisahu he'Anan va'Yera Kevod Hashem" (Bamidbar 17:7), "v'Hinei Chevod Hashem Nir'ah be'Anan" (Shemos 16:10).
Radak (Melachim I, 8:12 citing Targum Yonasan: "Ba'Arafel" means 'in Yerushalayim', i.e. there He will make His cloud of glory dwell.
