Why does it say "hal'Olam Te'enaf Banu"?
Radak: How did this Galus last so long? Will You always be angry with us?!
Malbim: Surely Your anger will cease at some time!
Is Anaf the same as Af?
Malbim: No. Af implies that the anger is revealed via punishment. Anaf implies that He eradicates the anger via punishment. Af punishment can be partial. E.g. if one was liable 100 lashes, they strike him once and leave the rest for later days. Anaf punishment does not leave any Af or punishment.
What is the meaning of "Timshoch Apecha..."?
Radak: Will Your anger last for all generations?
Is "l'Dor va'Dor" the same as "l'Olam"?
Malbim: No. L'Olam is forever that is not divided. L'Dor va'Dor is separated according to generations. The verse says, will You have Anaf and finish Your anger against us via the full punishment? Will this punishment of eradication apply to us forever?! And if You will extend Your anger, to punish little by little, and divide it among two generations, one generation will be eradicated, and it will not continue until the end of generations!