Because he has never witnessed a miracle, Gersonides bases his observations on the biblical accounts. Adhering to Aristotle's thought, Gersonides presents some basic assumptions, such as (1) God cannot intervene in nature, (2) God cannot change His will, (3) Nature behaves in accordance with laws. According to Gersonides, miracles cannot be a regular occurrence since natural phenomena and laws regularly changing through miracles would signify a defect in the natural order. Furthermore, an event that has already taken place cannot be reversed miraculously as if it has not taken place. Gersonides concludes that while God is the source of miracles, miracles follow the laws of nature. If they seem magical to human beings it is because these exceptional phenomena exist on a higher level of nature than the level with which human beings are familiar and comfortable.

The Lord said to Moses and Aaron, "When Pharaoh speaks to you and says, 'Produce your marvel,' you shall say to Aaron: Take your staff and throw it down before Pharaoh: Let it become a serpent. Moses and Aaron came to Pharaoh, they did thus as God had commanded. Aaron threw down his staff before Pharaoh and before his servants, And it became a serpent. (Exodus 7:8-10)

For example, Gersonides writes that the miracle of Moses' staff turning into a snake is just a speeding up of what would happen to the staff in the normal course of nature. Given enough time, the staff would have changed its properties and turned into a snake anyway. The miracle is the instantaneous aspect of the event,

". . . the turning of a stick into a snake can be accomplished by natural processes over an extraordinarily long period of time by the stick acquiring its form [i.e., of the snake] and relinquishing [its own] form until it becomes a snake. The miracle is thus in its being generated [i.e., the snake] without intermediary steps which normally occur in the course of nature. . . . Nothing can be generated miraculously if it cannot also be generated by natural process over an extended period of time."

Gersonides observes that a prophet is always present when biblical miracles take place. The prophet is able to predict the miracle, or else he brings it about through prayer. Sometimes he performs the miracle himself, and sometimes it occurs for his benefit. The prophet's perfected intellect allows him to commune with the higher laws of nature that normal humans don't understand and can't perceive.

Gersonides further observes that the biblical miracles always have a purpose that forwards a good cause or avoids a bad one, although the Exodus miracles puzzle him: the Egyptians, although they witnessed the same miracles as the Israelites, derived no good from them. Further, the Israelites did not seem to derive as much good from the miracles as they should have: they remained a "stiff-necked people."

There are some restrictions on the scope of miracles in God's creation: only the laws of nature are affected by miracles, not logic or mathematics. And celestial bodies not involved in miracles, thus the sun didn't really stand still as recorded in Joshua 10.

Eisen, Robert. Gersonides on Providence, Covenant, and the Chosen People: A study in Medieval Jewish Philosophy and Biblical Commentary (Albany: State University of New York Press, 1995).