A Yid once related that his wife had a devastating illness, but, baruch Hashem, she emerged from it healthy. I asked him how long she struggled with the illness, and he answered: “Struggled? Not one day! You mean to ask, ‘How long did it take?’ this, I can tell you.”
Our supplication שמחינו כימות עיניתנו, gladden us according to the days You have afflicted us doesn’t mean that we sing a different song—a happy song in the place of a sad one. It means we should sing the same songs we sang when things were dire. Then, we were close to Hashem through the pain, and now we sing the song again to thank Him for the yeshuah.
All the situations a Yid experiences in his life have a name: deveikus in Hashem. שמחינו כימות עיניתנו means that a person lives with Hashem in all his situations and in all eras of his life. This Yid says, “Ribbono shel Olam! I was together with You when I was in doubt and in pain... later I was together with You when I had worries... and I didn’t depart from You when worry was mixed with doubt. I was with You even when I was certain that I had brought these problems upon myself, and I remained with You when I came to my senses and realized that the Ribbono shel Olam runs the world with a clear cheshbon, no matter what we do. And, of course, I was there with You when I ultimately saw the yeshuah.”