Why does it say "v'Avo'ah"?
Malbim: Only to come to there, to gather the dispersed of Yisrael, I need help and salvation - but when I am there, I will go by myself to the Mizbe'ach.
Why will he come to the Mizbe'ach?
Radak, Malbim: To offer Korbanos, like initially.
Why does it say "El Kel Simchas Gili"?
Radak: I have no Simchah other than Hashem. He is the Simchah of all my Simchos. It is Samuch [to Gili] due to the great level of Simchah, like "Melech Melachim" (Yechezkel 26:7).
Mesilas Yesharim (Perek 19): David already reached a great level of knowledge of Hashem, therefore his heart was so happy.
Malbim: I will go to 'see' Pnei Hashem, since He is my Simchah.
Why will he thank with a Kinor?
Radak: This is like initially - they played musical instruments at the time of Avodah.
For what will he thank Hashem?
Rashi: For taking him out of exile.
Why does it say "Elokim Elokai"?
Radak: Then, all will say that He is Elokai, and He did not abandon me in exile.
