Why does it say "Ki"? Is this why David may not build the Beis ha'Mikdash?
Vilna Gaon 1 : David thought that he did two improper matters. (a) He lives in Beis Arazim - "ha'Es Lachem Atem Lasheves b'Vateichem Sefunim [veha'Bayis ha'Zeh Charev]" (Chagai 1:4). (b) Aron ha'Elokim is in a tent. Hashem answered, (a) you will not build the Beis ha'Mikdash - therefore you may live in Beis Arazim. (b) If Shamayim blocks a matter, because it is not time for it, or the person is not proper for it (he is not culpable).
Hagahah (verse 10): The Vilna Gaon's son wrote this in the name of his father. (PF)
What is the meaning of "va'Ehyeh me'Ohel El Ohel"?
'Rashi': I was transient, [Radak - from Ohel ha'Mes in the Midbar to Gilgal,] from Gilgal to Shilo, from Shilo to Nov, and from Nov to Giv'on. In all these places, the Aron and Mizbe'ach were under curtains. When the Aron was in Kiryas Ye'arim, the Mizbe'ach was in Nov [initially] and [later] in Giv'on 1 .
Ba'al ha'Turim citing the Rosh: It says me'Ohel in three other verses - "va'Yetzei me'Ohel Leah" (Bereishis 31:33), "me'Ohel Mo'ed Leimor" (Vayikra 1:1) and "Yitatzcha la'Netzach... v'Yisachacha me'Ohel" (Tehilim 52:7). When the Mishkan was set up, Bamos were forbidden - Hashem called to Moshe specifically from the Ohel Mo'ed. After they crossed the Yarden, Bamos were permitted until they came to Shilo - "va'Yetzei me'Ohel Leah (the Mishkan, which Betzalel, a descendant of Levi, built) va'Yavo b'Ohel Rachel", i.e. Shilo, in Yosef's portion. Then, I went "me'Ohel El Ohel" - from Shilo to Nov, from Nov to Giv'on, and from Giv'on to the Beis ha'Mikdash, and then Bamos were forbidden forever - "Yitatzcha la'Netzach... v'Yisachacha me'Ohel."
Malbim (from Zevachim 112b): It says (Shmuel II, 7:6) "b'Ohel uv'Mishkan" ? this refers to Shilo, which had a Mishkan (building) below, and an Ohel (curtain) above.
Why does it say "umi'Mishkan"?
'Rashi': It means umi'Mishkan El Mishkan. Radak - this is understood, since it says "me'Ohel El Ohel."
