You're walking down the street when suddenly — bam! — a hard object with sharp edges hits you smack in the middle of the forehead. You take a step back and, amazingly, the thing is still there, suspended in mid-air. It looks like what you would imagine a meteorite from outer space would look like: an asymmetrical chunk of ice and rock, glowing with heat on the inside, hard and cold on the outside.

You look around you. The lunchtime throng of sidewalk traffic flows on around you, mildly aware of the lone pedestrian obstructing their path (you), completely oblivious to the chunk of fire and ice hanging at forehead level in front of you. Apparently, you're the only one who has noticed it.

And then it hits you (this time inside your head): you've bumped into a piece of your past.

The seventh of the "ten plagues" to strike Egypt was the plague of hail, described in Exodus 9:22-35:

Moses stretched out his rod towards heaven, and G‑d rained hail upon the land of Egypt: there was hail, and fire flaring up within the hail, very grievous, such as there was none like it in all the land of Egypt since it became a nation...

All of the plagues, from the Nile turning to blood to the midnight death of the Egyptian firstborn, had a miraculous element to them, designed to "let Egypt know that I am G‑d" (ibid. 7:5). What's remarkable about the plague of hail is the supernatural way in which it ended.

As the Torah tells it, "Pharaoh sent and summoned Moses and Aaron and said to them, 'I have sinned this time; G‑d is the righteous one, and I and my people are the guilty ones...I will let you go.'" So "Moses went away from Pharaoh, out of the city; and he spread out his hands to G‑d; and the thunder ceased, and the hail and rain did not reach the ground." "Also those that were already in the air" explains Rashi in his commentary on the verse, "did not reach the ground."

What is the deeper significance of this strange phenomenon? The Lubavitcher Rebbe explains that Pharaoh's suspended hailstones emphasize the underlying dynamics of sin, punishment and repentance.

When we talk about an evil deed being punished by G‑d, many envision a supernal judge entering sins and failings into a cosmic accounts ledger, tallying up the debits, and meting out misfortunes as "retribution" or revenge. The truth runs deeper than that. According to the great Jewish thinkers, punishment is the result of sin rather than its retribution. When a person jumps out of a third storey window and breaks a leg, one might say that he was "punished" for his reckless deed; but it would be more precise to say that the Creator instituted certain laws of  behavior in the physical world — such as the laws of gravity, kinetic energy, etc. — which "dictate" the broken-leg result of jumping out of a 3rd-storey window. By the same token, the Creator also instituted spiritual laws of behavior, which dictate that evil deeds bring misfortune upon their perpetrators.

So while Pharaoh's suspended hailstones may have violated the laws of physical nature, they were consistent with a more primary nature — the spiritual nature of creation which precedes and underlies its physical nature. The moment that Pharaoh repented his evil ways, expressing regret over his deeds ("I and my people are the guilty ones") and resolve regarding the future ("I will let you go") — the moment that the spiritual cause of the plague was no longer — the plague too, ceased. For a single hailstone to have moved even one millimeter closer to striking the land of Egypt would have violated the basic law of creation that the spiritual reality affects the physical reality, and not vice versa.

Nevertheless, the hailstones that were already in the air did not disappear. Pharaoh's repentance had the power to stop the future results of his behavior, but not to undo the past. By stopping the cause (his refusal the let the people of Israel go), he stopped its result (the plague of hail); but the hailstones which had resulted from his past deeds, he could not undo.

Life is a journey (or a river, a road, a rollercoaster — pick your cliché) in which we move on, leaving the past behind. But though we may have left it behind us, the past still exists. And as long as the past still exists, its results also remain in existence, hailstones suspended in midair.

There is, however, a deeper level of teshuvah (repentance) that can change the past. A teshuvah that draws on the timeless core of our souls to effect such a radical change in our life's trajectory that it redefines the significance — and thus the results — of our past failings. No more hailstones to hit you on the forehead as you walk down street.