Whose supplication is it?

What's the story of this supplication?

Who was Kumayl?

He was Kumayl bin Ziyad al-Nakhay. He was one of Imam Ali's companions. He was a noble man. His people obeyed him. He came from Yemen. His family inhabited Kufa during Imam Ali's Caliphate.

Abid al-Rahman bin al-Ashath led a revolution against al-Hajjaj. Kumayl joined the revolution. He led the Qur'an Readers Battalion.