What are the differences between selichah, mechilah and kaparah?

Question

In reflecting on these three terms, selichah, mechilah and kapparah, they are often thought of simply as synonyms of forgiveness.

But trying to focus on their specific meanings in the context of the judgment of the Heavenly Court and how they are used in the liturgy of Rosh Hashanah and Yom Kippur suggests that they are actually three different and distinct requests which apply to different circumstances.

In particular, when considering the conclusion of the confession of Yom Kippur which speaks of the סלחן לישראל and the מחלן לשבטי ישרון, the first two categories. But then goes further requesting no suffering, afflictions or severe illnesses, which would suggest a connection to kapparah.

How are we to understand the meaning of what we are asking from G-d, the Creator of us all?

Answer 1

The Shaloh explains that they're increasing level of forgiveness corresponding to decreasing levels of sinfulness:

כפרה לחטאים. ומחילה לעונות. וסליחה לפשעים

שחטא הוא השוגג מתפללים שימחקם לגמרי כאלו לא היו מעולם. וזה ל' כפרה כמו אכפרה פניו וגו'. ומחילה לעון כי שם נשאר שום רושם. וסליחה שהיא אריכות אף לפושעים הם המורדים כי עליהם יום הכפורים תולה

For חטא, which is an inadvertent sin, we pray that He should erase them completely, like they never happened. This is [indicated by] the term כפרה, similar to "I will appease him." (Genesis 32:21) [The weaker term] מחילה corresponds to עון, because it leaves some trace behind. סליחה connotes clemency to פושעים, the wanton sinners, because Yom Kippur only suspends [judgement] for them.

Answer 2

In the back of the Artscroll Machzor on Yom Kippur (p.860) on the part of vidui where we read:

ועל כֻּלָּם אֱלֽוֹהַּ סְלִיחוֹת. סְלַח לָֽנוּ. מְחַל לָֽנוּ. כַּפֶּר לָֽנוּ

And for all of these, G-d of pardon, pardon us, forgive us, grant us atonement.

It writes as follows:

This is a progression from a smaller to a greater degree of forgiveness. סלח, forgive us, i.e. give up the right to punish us, מחל, pardon us, i.e. do not even harbour resentment or ill will against us; and כפר, atone for us, i.e. remove any effects of our sin as if we had never committed them. (Abarbanel)

According to Malbim and R' Hirsch, these terms go from a greater degree of forgiveness to a smaller degree. סלח connotes total forgiveness; מחל means a permanent waiver of the right to punish, even though the sin has not been completely forgiven; כפר - from כפרה, cover - implies only that the sin is hidden from sight, so that the punishment is suspended temporarily.

In Pathway to Prayer by Rabbi Mayer Birnbaum he adopts the first approach, and translates it as:

סְלַח לָֽנוּ - Forgive us for the sins themselves

מְחַל לָֽנוּ - Pardon us for the insult caused to Your Honor by our sins

כַּפֶּר לָֽנוּ - (and) atone for us as if they had never occurred.

Answer 3

Selicha—forgiveness.

Mechila—annulment of debt. Completely as if wrongdoing never happened.

Kapara—retribution. Taking payment for the debt. Punishment to result in forgiveness.