It would seem that each betrothal between Hashem and the Jewish people has a theme, or condition. The first is an everlasting relationship. The second is a relationship based on righteousness, justice, kindness, and mercy. The third is a relationship of trust in the Almighty; just like one can trust an expert in his or her field, so too the Jewish people can trust Hashem, who is an expert in everything, to take care of them and every Jew, young and old, will acknowledge that.
Why was the theme of the first betrothal one of an everlasting relationship, especially if the Radak just finished saying that Hashem knew it would not be permanent, and the Jewish people would go into exile again? On the contrary, it would make more sense for the third betrothal to be first, as we actually saw that Hashem showed His mastery over creation with the wonders of the ten plagues and his ability to take care of the Jews by taking them out of Egypt and guiding them in comfort with the Clouds of Glory through the barren desert. Indeed, the Jewish people reciprocated with the highest levels of faith in Hashem, from the youngest to the oldest, from the lowly maidservant to the greatest leader. It also makes sense for the theme of the first betrothal to be third, for when Moshiach comes and we are all redeemed from our current exile, then there is a guarantee that there won’t be any more exiles. This means our betrothal will be permanent; so shouldn’t Hashem have flipped the betrothals around?
We learn from here an important lesson in building a relationship. It must start with an everlasting, permanent commitment. No matter what bumps in the road may come, if there is a commitment to never give up, then problems will be solved. Without this commitment it does not matter how amazing and incredible the other person is, or how merciful and kind he or she might be, if the relationship does not start with this strong, everlasting commitment, then any excuse to break off the relationship could more possibly succeed.
Im yirtzeh Hashem when we are redeemed, speedily in our days, it will be with miracles similar to those of our redemption of Egypt, if not even more magnificent. Then we will all acknowledge Hashem security and benevolence forever and ever!