1)
Why did he vow about his house?
1.
Radak: This is like he said to Nasan ha'Navi "Anochi Yoshev b'Veis Arazim v'Aron ha'Elokim Yoshev b'Soch ha'Yeri'ah" (Shmuel II, 7:2).
2)
Why did he say "Im Avo" and "Im E'eleh"?
1.
Radak: This is an exaggeration. I.e. I will not enjoy sitting in my house or resting on my bed until I find a place for Hashem.
2.
Malbim: Refer to 132:2:1:3.
3)
What is "Eres Yetzu'ai"?
1.
Radak: A bed on which are esteemed mattresses proper for a king.
