Sforno on Exodus 6:6/ספורנו על שמות ו׳:ו׳

1'לכן אמור לבני ישראל אני ה. The Torah speaks of three reasons (stages of the redemption) why G’d at this time reveals knowledge about Himself which He had not revealed previously.

21) והוצאתי אתכם מתחת סבלות מצרים there will be an immediate cessation of the Israelites performing slave labour for the Egyptians.

32) והצלתי, on the day the Israelites would depart from Ramses, when they would cross the border out of the land of Egypt.

43) וגאלתי, on the day the pursuing Egyptians would be drowned in the sea, as testified in Exodus 14,30 ויושע ה' ביום ההוא, “on that day the Lord orchestrated salvation, etc.” After the death of the ones who enslaved, the enslaved are obviously free.