Know that, at its simplest, repentance is returning to God. It is the spiritual traveler’s first step on the path to truth.
Repentance starts when you clearly see that sin is a fatal poison, and that the carnal appetites are like honey in which there is poison; it is sweet for a moment but painful in the end.
Among these sweet poisons are adultery, intoxication, theft, and disobedience to one’s parents.
Know that the antidote for the poison of sin is repentance.
The Rules of Repentance
Fear
When one learns they consumed poison, the immediate emotional reaction is fear for whether they will live or die.
Regret
The next emotion is regret for having mistakenly consumed the poison – sin too is a poison, and one should fear the punishment of the hereafter; also one should regret having committed the sin.
Thus, the basis of repentance is fear and regret.
After fear and regret, one should then resolve to do three things:
1- The Past
One is for the past: to make up for the sin. For example, if you did not pay your annual charity you should do so now.
2- The Present
Another is for the present: to abandon the sin.
3- The Future
And the third is for the future: to restrain oneself from future sin and work towards the Hereafter.
One who delays repentance is like the man who is asked to uproot a tree and responds: “the tree is strong and I am weak! I’ll wait until next year.”
The fool doesn’t realize that the tree only grows stronger. The carnal appetites are like the tree, they gain strength every day; the sooner you start to work against them, the easier it will be to overcome them.