Malbim (here and in Melachim I, 5:17): Since his son will have serenity, he can build it l'Shem Hashem. David, who did not have serenity, could not, for he would profit through it, like Nasan said that building it will bring rest from enemies.

Malbim: Hachanah is the start of the kingship, and Konenus finishes the building of it.