בִּ֭רְכַּי כָּשְׁל֣וּ מִצּ֑וֹם וּ֝בְשָׂרִ֗י כָּחַ֥שׁ מִשָּֽׁמֶן׃
금식함을 인하여 내 무릎은 약하고 내 육체는 수척하오며
Reshit Chokhmah
With all this, we find that David accepted upon himself afflictions and fasts, as it says “My knees were week due to fasting” (Psalms 109:24), and that which he was troubled from his kingdom was because his sin was that he had Uriah killed with the sword of Ammon, as it says in the Zohar in Beresheet. But the punishment for what he sinned with Uriah was written and he accepted, meaning what Nathan the Prophet said to him “I will raise up evil against you out of your own house” (Shmuel B 12:11). One who damages his Brit must surely suffer afflictions and fasts all his life as David did.