"What should be remembered is that we are not expected to do teshuvah in a conventional universe.
We do teshuvah in a universe that is quite unaware of physical laws.
A universe in which the present, the future, and the past merge into a timeless duration.
A universe in which a lethal arrow is liable to fly back and to be as free of all suspicion as if it had never left its quiver.
In a word, through repentance we penetrate into a sort of physical weightlessness, where we can choose, for instance, to reverse our conventional value by replacing a plus sign with a minus sign, or vice versa.
There are things on this lowly earth of which we are particularly fond, but each of us has his own peculiarities in this regard.
To give money, for instance, is for some of us a molehill, whereas to apologize for having offended someone is a mountain.
If you offer a sacrifice to God, make sure that you offer what really costs you dear, for God would not appreciate a fool's deal."
–Rabbi Adin Steinsaltz
From "Teshuvah" in The Strife of the Spirit, p.99, by Rabbi Adin Steinsaltz