Redemption is described as a process. However, the process itself is not redemption. Even though we might think we can point to a specific event or moment in time when the process began, we can't say, "it has begun, therefore it has arrived", anymore than backing the car out of the driveway for a 200-mile journey is in any way equivalent to arriving at the intended destination.
Sunrise is also a process, a gradual lightening of the sky in the east until the sun itself finally breaches the horizon. But, we don't say the sun has risen until the precise moment in time that this happens, at a precise moment in time we call sunrise. It's the same with the geulah.
I was pondering how it could be that the impending arrival of the geulah brings a greater and greater light into the world while the world itself seems to be sinking ever deeper into darkness and I had a chidush. It's like when the pillar of fire and the cloud came between Bnei Yisrael and the Mitzrim at Yam Suf the night before the sea split.
Rashi on Shemot 14.20 - "The pillar of fire [illuminated] the night for the Israelites, and it went before them as it usually went all night long, and the thick darkness [from the cloud] was toward the Egyptians."The darkness is real and the light is equally real and they exist side by side. The fact of the darkness does not negate the light, it reinforces it. Which one we see and which reality we live with depends on which side we are standing on. It's our choice. And that is why the 4/5ths of Jews who did not want to leave Egypt died during the plague of darkness! In this instance, too, the Jews enjoyed light while the Mitzrim were sunk in a tangible darkness.
Awareness of the deepening darkness in the world should prick our hearts and cause us all to cry out to Hashem like we cried out on the edge of the sea. But, we cry out, not just because of the fear and hopelessness that darkness engenders, but because we can see the light alongside it, getting brighter and brighter and we have no more patience to wait. Our cry is equally a longing for deliverance from the darkness and the embrace of the light.