Why does it say "Gam Ani..."?
Radak: Just like You increase to do good, so I will increase to thank You with harp and lyre.
Malbim: Also I will thank for the good that You did for me. Also refer to 71:22:4:2.
Why does it mention "Amitecha"?
Radak: He said that He will take us out of Galus; when He will do so, He will fulfill His Emes.
Will he sing only then?
Radak: Yes - I cannot do so in Galus, for our Simchah was marred - "Talinu Kinoroseinu", "Eich Nashir Es Shir Hashem Al Admas Nechar" (137:2, 4).
Why does it say "Kedosh Yisrael"?
Radak: Then Your name will be sanctified within Yisrael.
Malbim: I will sing also encompassing praises due to Your being Kedosh Yisrael.
