Who will mention "Chasdei Hashem"?
Rashi: The Navi will remind Yisrael of His Chasadim.
Radak: Regarding the great Chasadim that Hashem will remind do for His nation, which he showed to the Navi, he said that He will remind people of the Chasadim that He [already] did for them, so they will thank and praise His name. It says Chesed, for they rebelled against His word, and He benefited them.
Malbim: This discusses how Yisrael, in their afflictions, remember the wonders that He did for them in early days. Their Ru'ach searches, why did He turn back His right hand, and they dispute with Him about this. His answer and consolation is until Perek 66.
What does the verse teach about "Tehilos Hashem k'Al Kol Asher Gemalanu"?
Malbim: I will praise Him according to what He bestowed on us. One cannot praise Him Himself, only based on His Chesed and deeds; from this we recognize His praises.
What does the verse teach about "Rav Tuv"?
Rashi: I will remind Beis Yisrael of the great good that He bestowed to them in His mercy.
Radak, Malbim: He did great good to Yisrael "in His mercy and great Chesed", not according to their deeds. Malbim - one who has mercy, he saves because he cannot see the other's affliction. He only saves from the affliction. One who does Chesed, it is from a wide heart and generosity, also for one who is not afflicted and crushed. Beyond saving from the affliction, he does other benefits. Also, one who has mercy, he does not seek thanks for his good. One who does Chesed, one must thank him for his Chesed.
