The miracles that God performed during the exodus from Egypt were meant to strengthen belief in God and His prophets. God’s hand is evident in the miracles that He has performed for the people of Israel throughout the generations.

The greatest of the Creator’s benevolences to humanity, and the strongest proof of His existence, is the Torah, given to Moses His prophet, of blessed memory, as well as the signs He performed through him, and the way he changed nature showing awesome wonders, in order that we would believe in the Creator, may He be blessed, and His prophet. As it is written: “Israel saw the great power that the Lord wielded against Egypt and the people feared the Lord and believed in the Lord [and in Moses, His servant]” (Exodus 14:31). And it states: “You have been shown in order to know that the Lord, He is the God; there is no other besides Him” (Deuteronomy 4:35). If a person seeks nowadays to see something similar to those matters, he should take a truthful look at our survival among the nations since we went into exile and how our affairs have been while among them, notwithstanding that we do not agree with them, both with regard to the esoteric and the revealed, and they know it. (Rabbeinu Baĥya ibn Pakuda, Ĥovot HaLevavot, Sha’ar HaBeĥina 2:5)

Further reading: For rabbinic stories of wonders and miracles, see A Concise Guide to the Sages, p. 347.

The miracles that took place in Egypt, like the ten plagues, establish the belief that God providentially oversees everything that happens in the world and He has unlimited control.

The goal of the miracles of the exodus from Egypt was to implant within us belief in God:

The Torah says with regard to the wonders [in Egypt]: “…so that you will know that I am the Lord in the midst of the land” (Exodus 8:18). This refers to divine providence, indicating that He hadn’t left the world to happenstance – as is their opinion. He also said: “… so that you will know that the earth is the Lord’s” (Exodus 9:29), to teach that the world is created, [not eternal,] and it is His, for He created it ex nihilo. He also said: “… so that you will know that there is none like Me on the entire earth” (Exodus 9:14), to indicate His omnipotence, that He controls all and no one can in any way limit His activities. For the Egyptians either denied or doubted all of these truths. We see from here that great signs and wonders are reliable witnesses for belief in the Creator and the entire Torah.

Remembering the exodus from Egypt and the miracles that accompanied it is a way to transmit belief to subsequent generations:

Since the Holy One, blessed be He, will not perform a sign or a wonder in every generation before any wicked person or scoffer, He commanded us to make a constant reminder and sign for what our eyes saw, to pass it on to our children, they to their children, and to continue until the last generation. (Ramban, Commentary on the Torah, Exodus 13:16)