Here is another long repost from Torah.org which discusses how Teshuva works concerning David and those who rebelled against him..
http://www.torah.org/learning/ravfrand/5765/kisavo.htmlRabbi Frand on Parshas Ki Savo
Selichos: It Pays to Be 'First In Line'The opening poetic composition of the Motzaei Shabbos [Saturday night] Selichos liturgy (the very beginning the pre-Rosh Hashana Selichos) begins with the words "B'Motzaei Menucha Kidamnucha techila" [With the going out of (the day of) rest, we are first to greet you]. The Izbitzer Rebbe notes that the two words "Kidamnucha techila" [we are first to greet you] introduces the entire idea of Selichos.
Why, after all, do we say these penitential prayers 4 to 10 days before Rosh Hashanna? This is not, formally, the "High Holiday period," which technically begins on Rosh Hashanna and runs through Succos. What does Selichos accomplish in this period that is neither -- strictly speaking -- a period of either judgment or atonement?
The Izbitzer Rebbe explains that the idea behind Selichos is that the earlier we get started asking forgiveness from the Almighty, the more successful we will be. The Izbitzer Rebbe cites a proof to this idea from a Biblical incident.
Dovid HaMelech [King David] had a very tumultuous life. One of the indignities that he suffered was having his monarchy overthrown by his son, Avshalom. In one of the most pathetic chapters of the entire Tanach [Shmuel II 15], Dovid HaMelech had to leave Jerusalem with his family and entourage to flee from his son who took over the throne. In this moment of great personal tragedy, Shimee ben Gerah took the opportunity to add insult to injury. He laced into the King and bitterly cursed him. Shimee figured that at this point, Dovid HaMelech's kingship was ended. Shimee, who had a personal grudge against Dovid HaMelech, mercilessly cursed the fleeing monarch.
Dovid HaMelech eventually retook the monarchy and returned to Jerusalem. All the people who sided with the wrong side, and especially Shimee ben Gerah who had cursed the king, were fearful for their lives. In fact they were deserving of death, for in the times of the Biblical monarchy, one who rebelled against the king (mored b'Malchus) was deserving of the death penalty. The Rambam rules that the King can personally –- without trial -– execute such rebels.
Shimee ben Gerah knew that he was a 'dead man'. So what did he do? "Shimee son of Gera, the Benjamite who was from Bahurim, hastened and went down with the men of Yehudah to greet Dovid HaMelech." [Shmuel II 19:17] He reached the King and told him "...For your servant knows that I have sinned, and here I have come today, first among all the House of Yosef, to come down and greet my master the king." [Shmuel II 19:21].
Shimee emphasized that among the thousands of people who were asking Dovid HaMelech for mechila [forgiveness], he was one of the first. "I know I did wrong. I know I sinned against you. I know that I should lose my life for it. I apologize and I am sorry. I am not even going to wait in line to tell you this. I want to be the FIRST person that has the opportunity to express my remorse."
The Izbitzer Rebbe says that this exactly parallels what we are doing in our pre-Rosh HaShana Selichos.
Strictly speaking, one could wait until Rosh HaShannah to approach the Almighty with these requests. Theoretically, one could even wait until Yom Kippur. There are procrastinators in life –- such as the fellow who always files his (U.S.) income tax forms on the night of April 15th! The Jewish counterpart of the April 15th tax filers are those who wait until Neilah (the final Yom Kippur prayer) to make their sincere request to the Almighty for Forgiveness and for Mercy.
The difference is that the U.S. Internal Revenue Service (IRS) does not care if the tax forms are filed on February 1st or just before midnight on the 15th of April. As long as the envelope is post-marked by April 15th, it is all the same to the IRS. However, if one is wise enough and spiritually sensitive enough to try to "catch the Master of the Universe early" -- to be "first in line" -- that does make a difference! Even if one's sins are as incriminating as those of Shimee ben Gerah against Dovid HaMelech -– humiliating and abusing the king –- nevertheless it pays to be "first in line."
Shimee ben Gerah should have been a 'dead man'. But his haste to see the king paid off. Dovid HaMelech did not kill him. He did not even direct his son Shlomo [Solomon] to kill him. Why did this wicked person merit such merciful treatment? Shimee ben Gerah merited merciful treatment because he knew the secret of "coming first" to plea for his life.
This year, there are eighteen days between the start of Selichos (on the night following September 24th) and Yom Kippur (October 13th). One might ask -– why do we need to recite Selichos this Motzai Shabbos? What is the rush? We have plenty of time!
But there is significance to coming early. This tone of Selichos is set with the opening words of the first Selicha-poem recited on the Motzaei Shabbos when we begin to recite the first penitential prayers: "B'Motzaei Menucha kidamnucha techila." At the conclusion of resting, we are first in line to greet you.
It is all a matter of showing up early to sincerely say and demonstrate "I am sorry!" Let us be like Shimee ben Gerah regarding this one matter of showing up first, rather than waiting for the masses to come and present their requests for forgiveness.