In the short form of tachanun (said most frequently in Ashkenaz circles), two pesukim (verses) from Shmuel Bais כד:יד [Samuel 2 (24:14)] precede kapitel ו (Tehillim Psalm 6), starting from the second verse. Tachanun is also referred to as נפילת אפיים (nefilas apayim). This was composed when King David was sick and in pain, and he recognized the pain as a release for the soul burdened by the shackles of sin.
