Why does it say "b'Nas'i Yadai"?
Radak: This is like one who requests help from another. He spreads his hand to receive his help. This is like "v'Chapav Perushos ha'Shamayim" (Melachim I, 8:54), "Efros Es Kapai El Hashem" (Shemos 9:29). They are lifted up towards Shamayim.
Malbim: Do not wait for my prayer. Once I lift my hands to Devir Kodshecha, answer me.
What is "Devir Kodshecha"?
Radak #1: It is the house in which the Aron was (the Mikdash was not built yet). The honor is there.
Radak #2: It is Shamayim, just like Shamayim is called Heichal and Har Kodesh, like I explained (refer to 15:1:3:1).
Why does it say "El Devir Kodshecha"?
Radak #1: It means bi'Dvir Kodshecha. Also "v'Nasata El ha'Aron Es ha'Edus" (Shemos 25:16, is like ba'Aron).
Radak #2: It is simply El Devir Kodshecha. He lifts his hands towards that place, like towards Shamayim. [That place] is like a ladder for Tefilah to ascend to Kisei ha'Kavod - "va'Tavo Sefilasam li'M'on Kodsho la'Shamayim" (Divrei ha'Yamim II, 30:27).
